# AM3 HyperTransport, what /really/ is the default speed?



## Formula350 (Jul 7, 2010)

OK so I'm still pretty new to the AM2/3 scene, and any OC gurus look for a thread in the OC section. So I'm a bit out of touch with what should run at what. The first experience I had with my new system was in the form of the Athlon II X2 250u (ULV 1.6GHz), which I bought for a neighbor's build, but used it to test my system out till I could get my own. Since I'm also a fan of OCing I decided to light a fire under that 250u's ass  So all my experience/confusion is stemming from that crazy time  

To not jump too far off topic, I was able to get the CPU, NB and HT all running 1:1 at 2.9GHz (and stable I might add) which I thought was pretty good for my first go at overclocking something newer than my S939 X2 3800+  THEN I got the Phenom II and shit went down hill  To keep this on point: I can't get the HT clocking any faster than 2400MHz! Default values show 2000MHz, but Giga's site and NewEgg's product page both show 2600Mhz (or just 5200M/Ts in the case of Giga's site, which = 2600MHz)  Sooo.... which is it?! 

Then any know why the Phenom II would seem to cripple my overclock compared to the 250u, which being an Ultra-Low Voltage chip I would have thought it wouldn't OC for beans... Not to step on the OC section's toes, but it's far more than just the HT that I can't OC anywhere near what I could when the 250u was in here!


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## Dent1 (Jul 7, 2010)

Overclock the processors default bus speed (HT) and the HT link bus will also increase higher as a result. Either way increasing the HT link bus will not yeild much of a performance increase.


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## Formula350 (Jul 7, 2010)

Dent1 said:


> Overclock the processors default bus speed (HT) and the HT link bus will also increase higher as a result. Either way increasing the HT link bus will not yeild much of a performance increase.



The "Base Clock" that you are talking about is the HTT, not the HT  And I know HOW to overclock it all, that isn't the issue  As I said, I was able to get the speed with the 250u processor up to 2.9GHz, it is just that the Phenom II isn't allowing for any of the clocks that the 250u was capable of and as a result it has left me a bit confused.


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## JrRacinFan (Jul 7, 2010)

You have the added L3 cache on the CPU's NB that you have to keep stable now. Bump your CPU NB voltage up +0.1v. That should allow you to get closer to to the ~2.5Ghz NB clock realm. Also every single AM3 based cpu I had defaulted to 2ghz HT Link.

@Dent1

In my experience with a couple of these PhII chips, keeping a 1:1 HTLink:NB seems to help stable out the cpu (up to 2.4Ghz).


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## Dent1 (Jul 7, 2010)

Its not surprising no two processors are the same. My athlon II X4 can tolerate a HT link @ 2700Mhz and a NB @ 2700MHz Prime 95 stable with no additional voltages needed, but some people with the same CPU can not. All you can do is put more voltage through.

Also, my scores are higher in 3DMarks 06's CPU benchmark and WPrime with the HT Link @ >2400Mhz and 2000Mhz than @ 2700Mhz, shoot to high on the HT link and the performance degrades.


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## Formula350 (Jul 7, 2010)

JrRacinFan said:


> You have the added L3 cache on the CPU's NB that you have to keep stable now. Bump your CPU NB voltage up +0.1v. That should allow you to get closer to to the ~2.5Ghz NB clock realm. Also every single AM3 based cpu I had defaulted to 2ghz HT Link.
> 
> @Dent1
> 
> In my experience with a couple of these PhII chips, keeping a 1:1 HTLink:NB seems to help stable out the cpu (up to 2.4Ghz).



Guess I wouldn't have thought the L3 would have any impact on the HT stability :\ But I've thrown so much voltage at this thing it isn't even funny. I actually went a bit crazy one night just to see if I could manage anything, but alas I couldn't. I can't even get the HTT up above 225MHz, where as with the Athlon II I was able to get 363MHz!!  I just don't understand what the issue is :\ Especially since this 555BE I got from cdawall and it did 4GHz for him, yet I can't even get 3800 stable 




Dent1 said:


> Its not surprising no two processors are the same. My athlon II X4 can tolerate a HT link @ 2700Mhz and a NB @ 2700MHz Prime 95 stable with no additional voltages needed, but some people with the same CPU can not. All you can do is put more voltage through. And of course I've tried everything at default clocks, and sometimes lower, with just the NB or HT up above 2400Mhz but still to no avail
> 
> 
> Also, my scores are higher in 3DMarks 06's CPU benchmark and WPrime with the HT Link @ >2400Mhz and 2000Mhz than @ 2700Mhz, shoot to high on the HT link and the performance degrades.



I noticed a strange thing like that with the 250u! If I had (one or the other but I can't remember which) the HT or NB like 200MHz lower than the other, it was a bit faster. I think it was the NB being a bit lower than the HT. At the time of my testing, I didn't know I could go 1:1:1 on them so the HT would've been like 2500MHz and the NB would've been 2300MHz. Which ever the combo, the memory bandwidth would go up a bit as well.


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## hat (Jul 7, 2010)

JrRacinFan said:


> Also every single AM3 based cpu I had defaulted to 2ghz HT Link.



My 240 defaults to 1600MHz. I run it at 2000 (250FSB) without issues.

I think it depends on your processor, motherboards just say 5200MT/s to show that that's that they're rated for... kinda like RAM, you might have a board that has a DDR2 1066 memory standard, but that doesn't mean you HAVE to run 1066 in it, it just means that's what it's rated to run up to.

There's not a huge performance impact on HT speeds anyway. I remember doing an extensive SuperPi test at all available HT settings, and the lowest HT speed was equal to the highest HT speed, within the variable margin of benchmarks.


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## Formula350 (Jul 7, 2010)

hat said:


> My 240 defaults to 1600MHz. I run it at 2000 (250FSB) without issues.
> 
> I think it depends on your processor, motherboards just say 5200MT/s to show that that's that they're rated for... kinda like RAM, you might have a board that has a DDR2 1066 memory standard, but that doesn't mean you HAVE to run 1066 in it, it just means that's what it's rated to run up to.
> 
> There's not a huge performance impact on HT speeds anyway. I remember doing an extensive SuperPi test at all available HT settings, and the lowest HT speed was equal to the highest HT speed, within the variable margin of benchmarks.



Right, multi-locked chips run their HT and NB at the highest available CPU multiplier. So my 250u ran @ 8x for a CPU, NB and HT speed of 1600MHz. Since all I could do with that is HTT clocking, I managed 363MHz for 2.9GHz across the board. And so I assume that the Phenom II's default on the HT speed is 2GHz, but the motherboard can support (stably) a speed of 2.6GHz? But since that CPU isn't technically specced for that, it is a crapshoot to get 2.6GHz to run stable?

I just reaaaaaaaaly need a solid AM3 overclocking guide  I've search to no avail. Coming from S939 I am just so out of the loop for what voltages generally yield the best OC headroom, and so forth. I mean for all I know I am cranking up certain voltages and I really don't need to, but by doing so I'm creating excess heat that is leading to more problems. Mind you I have tried my best now to volt back to default, down to the lowest point where everything is stable. But that again is causing some confusion, like why can I run my CPU at "Default" voltage which is reported by the BIOS (and AOD but nm it) as 1.275v vCore, but then in the Hardware Monitoring area it is showing 1.34v  I've told it to run lower voltage and at 3.7GHz it is still stable, but if that is the case why am I not scaling OC headroom with the increasing of voltage? *sigh* 

I'm just overall kind of bummed out with all this. I started out so strong with that 250u overclocking that I thought by getting a 4GHz capable CPU (bought it from cdawall) that I'd have a kick ass system with some sweet clocks of 4GHz, 2.9GHz and DDR3-1600 7-7-7  Anyone know of a program like the old school ones that kicked ass, which I can disable L3 cache? I realllly miss having a program like A64Info too, where I could clock do /almost/ everything I wanted (couldn't adjust HT speed), like adjusting the DDR speed (ratio) from in windows. I feel so spoiled from all that, and now when I can't it just feels like a chore to OC since I have to go through the BIOS


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## cadaveca (Jul 7, 2010)

All you should need to up is cpu volts(1.55v max), CPU/NB volts(1.425v max), and maybe, if a bit of HTT is used, some chipset/SB volts(1.325v max).

If you need to use more volts than what I listed, you need better cooling, or to scale back the clocks.

There are very few guides out there on AM3, but really, boards ahve progressed so much since 939 days that all of the guess work is now taken care of, and overclocking is not hard by any means any more. Set volts, find max of each bit, then glom htem all together, and you are good to go.


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## erocker (Jul 7, 2010)

If your board can't do 2600mhz HTT, then I would toss your board back to Gigabyte. I run mine at 2800mhz 1.25v.

Rest of it:

CPU: 4.1ghz 1.44v LLC enabled 1.46v under load
CPU/NB: 2800mhz 1.4v
HTT: 2800mhz 1.25v
NB volts: 1.22v


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## Formula350 (Jul 7, 2010)

erocker said:


> If your board can't do 2600mhz HTT, then I would toss your board back to Gigabyte. I run mine at 2800mhz 1.25v.
> 
> Rest of it:
> 
> ...





cadaveca said:


> All you should need to up is cpu volts(1.55v max), CPU/NB volts(1.425v max), and maybe, if a bit of HTT is used, some chipset/SB volts(1.325v max).
> 
> If you need to use more volts than what I listed, you need better cooling, or to scale back the clocks.
> 
> There are very few guides out there on AM3, but really, boards ahve progressed so much since 939 days that all of the guess work is now taken care of, and overclocking is not hard by any means any more. Set volts, find max of each bit, then glom htem all together, and you are good to go.



Just going to knock both of these out in one reply 

I WAS able to do 2900MHz on the NB and HT, but as I've been saying (not to sound snotty haha) that it is oddly now not possible with this Phenom II, as it was with the Athlon II  The voltage for the NB I'll explain below...

I don't have a Load voltage control, just the CPU PLL, DRam, NB Chip, NB/PCIe/HT Link PLL (I assume that is for stability), CPU-NB and then CPU. The CPU PLL is, from my understanding, the voltage that helps stabilize the CPU. I don't know if the 1.275-1.55v is bucked from that or what though, as 2.5V is it's default and "Redline" is 2.9v with "Danger Redline" at like 3v. I had that at 2.9v for the 250u and have tried 2.98v with the PhII, no help. DRam is self explanitory, and there is an accompanying voltage for it but when you adjust the normal DRam anything above it's default (1.5) it gets disabled so with my OCZ requiring 1.9v I have no option to change that heh. The NB chip voltage is defaulted to 1.3v since I have an 890GX, so to get 1000MHz out of the IGP you generally need 1.4v which is still "safe" for it, and I found 1.46v was better to get 1000-1075 stable but it isn't important now that I have 5770s. Yet I also had it that high when I was managing 2.9GHz  So I run that usually around 1.36v but I think it is almost default now with only being able to get 2.4GHz from the NB and HT, which at 1.4 to 1.5v it doesn't do anything to help the NB and HT. The NB/PCIe/HT PLL option is default at 1.8v but I've tried upwards into 1.98v with no luck, and the 250u ran fine at 1.88v. CPU-NB doesn't give a default but from what I can gather from AOD it is 1.175v (.1v lower than the 'assumed' CPU default of 1.275v). Then the CPU core is 1.275, but as I mentioned it would show 1.334 in the Hardware Monitor area. I think I originally had it set higher, but there was not help and I think I've discovered that whatever Default is (it's all called Normal on my board), then I am running that. So SOMEWHERE between 1.175 and 1.3v  Now the CPU vCore is not shown accurately in AOD or the BIOS, as "Normal" shows 1.275v, as does AOD even when I've set it to something more. I've got it set at 1.375v to run at 3.7GHz stable, which I've tried all the way to 1.6v temporarily to see if that would help get 4GHz. The closest I got at 4GHz was a post and got to the Boot Manager for 7, but it crashed and wouldn't post again. Resetting the BIOS to my stable BIOS profile and all is well. I only did that once and since I have (according to FrostyTech's accumulated data) the best AMD HSF (125W, and like 1st or 2nd best for Intel (150W) heh So heat is not an issue ever. I have not seen the temp go over 45c under IntelBurnTest 1GB load, which is only about 1/2 speed on the fans  (1800RPM and very quite still) The vCore doesn't show selectable voltages though (even if the BIOS has it available and not "hidden", but it doesn't show up), it uses the +0.*xxx*v above normal, so I don't know if since default is "1.275v" that 1.55v is actually 1.491v or what  The 250u I believe reported 1.15v default vCore and 1.05v was the real-world default

I've tried every combo I can think of, tried BIOS revision F3 and F5 and F7c (none appear to offer anything over one another as far as performance), setting the CPU and NB multiplier lower and trying to get the HT up or the 3 lower with the HTT raised, and then any/every combo of those. Nothing gets the CPU stable over 3.7GHz, the NB/HT even POSTING over 2.4GHz (I may have gotten 2.6GHz to post but then crashed and had to reset), or the HTT to run over 225Mhz instead of multiplier OC  Sadly cdawall doesn't remember the exact settings he ran to get it to 4GHz, and it would do 4.2GHz but not stable by any means. 

Sooooo I'm at a loss!


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## erocker (Jul 7, 2010)

This post isn't really helpful but from what I've seen AMD + Gigabyte leads to walls of text and confusion. I've had two Gigabyte boards for AMD and both have gone back to the retailer. That being said did you do the simple stuff like reseting the CMOS and flash the latest bios? When you are trying for higher HTT and NB does it boot back into bios? Locks up? Tries to boot to Windows but cannot?


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## Formula350 (Jul 7, 2010)

erocker said:


> This post isn't really helpful but from what I've seen AMD + Gigabyte leads to walls of text and confusion. I've had two Gigabyte boards for AMD and both have gone back to the retailer. That being said did you do the simple stuff like reseting the CMOS and flash the latest bios? When you are trying for higher HTT and NB does it boot back into bios? Locks up? Tries to boot to Windows but cannot?



I've loved the other 2 Gig boards I had, the 762MPX Athlon MP one and then the S939 I upgraded to. That is what made me want to go with them again. I was able to overclock quite well with the S939 as well given it didn't have all the options that say, the highest end DFI board (which I acquired for free, that didn't work but I got to), yet they both overclocked everything the same! Though the DFI did allow for different memory clocks, but I questioned them as I was getting ProMOS chips to run at DDR560+ o_0

And I can understand if you didn't read through my 8 page report  Here is what I said 2nd to last paragraph: _"I've tried every combo I can think of, tried BIOS revision F3 and F5 and F7c (none appear to offer anything over one another as far as performance)"_. It also offered no additional help to OCing, which is what I meant by performance.

What happens USUALLY is the BIOS recovery kicks in to get you out of a failed OC, but oddly when I try to OC the NB or HT, 99% of the time it will get into a loop where it can't recover (doesn't post but I can hear it trying to restart based on fan fluctuations). Then I have to clear CMOS and load my profile back up. I think it has to do with the fact it doesn't reset the NB or HT under fail conditions. All it does is reset the HTT and CPU multi, but since I'm not OCing the HTT and it is set to 200MHz, the multi for the NB and HT are still OCing the system  If I could adjust their multi's in windows easier than I can, I could try to go that route, but that's a hassle since I need to use 2 programs. CPU-Tweaker to bump the NB (UnCore) higher and then I need to load AOD to adjust the HT higher, BUT since I can't adjust the HT higher than it's boot setting I am forced to adjust the NB first lol I'm sure I could adjust the NB first to get AOD to recognize it is a multiplier down from the max, but I suspect I wouldn't be quick enough and it'd crash.


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## cadaveca (Jul 7, 2010)

you don't need increased HTT. 2000mhz is adequate enough...2400mhz(8x300) is more than enough.


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## Formula350 (Jul 7, 2010)

cadaveca said:


> you don't need increased HTT. 2000mhz is adequate enough...2400mhz(8x300) is more than enough.



And I realize that, I really do. I just am more confused as to why the Athlon II allows all these higher clocks, when it is a budget CPU. Especially the fact that this one was a damn Ultra-Low Voltage model!! Then I toss in an unlocked enthusiast Phenom II and the system becomes, in essence, crippled 

So it isn't so much that I think I'll gain a bunch of locked up performance, but I'm more interested as to the _why_ it is occurring and then what I can do to rectify that. It's all a learning experience for me, and the more I know the better! That way later on, I can in turn help other people out


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## cadaveca (Jul 7, 2010)

It's quite simple. The Phenom II cpu puts more load on the motherbaord's power section, and the chipset as well, affecting how "high" it can go.

But, if you drop the HTT multi, you should have no issues scaling the base frequency.

At this point in the game, we are all current limited. It's nigh on impossible to actually kill a cpu, unless you got a really bad peice of silicon, due to motherboards now monitoring current, and adjusting things accordingly.

Before, we had to make "vdroop" mods to overcome built-in current limits. Nobody really talked aobut what the mod really does, but it does in fact introduce more current, allowing the voltage to drop less as current is consumed.

LLC modifies this same thing as well...but in a far different way.


So, anyway, Phenom2 consumes more current, but the same physical motherboard current limitations prevent it from going much further. Swapping to another board will fix the issue, provided it has an ample power design.

On CH3, I have no issues running 3000mhz HTT(300x10), and I did this with both C2 and C3 Phenoms. The current X6 cpus are only better at this than X4 parts...and soon new chips will have a 2400mhz base as well. 

The problem, unfortunately, isn't in the chips themselves...but in the board design, IMHO. However, since such speeds rarely make for any performance difference, I hardly see it as an issue.


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## Formula350 (Jul 8, 2010)

cadaveca said:


> It's quite simple. The Phenom II cpu puts more load on the motherbaord's power section, and the chipset as well, affecting how "high" it can go.
> 
> But, if you drop the HTT multi, you should have no issues scaling the base frequency.
> 
> ...



Makes sense, but wouldn't really cranking up the CPU PLL (which is the same as your LLC) allow for more stable power? I mean yes this thing is only a 5+1 design, but it amazes me that I can have a chip that will operate overclocked 500mhz on such minimal voltage, that at any higher voltage it simply won't increase it's headroom. After all (and this is an arbitrary current value) if a CPU is being fed the max a board will allow of 8A at 1.334v, the CPU is consuming 10.672W. Now feed that same maxed out 8A with 1.55v and it has 12.4W. Under the conditions I'm at, it would seem to me that the CPU is not maxed out for clock, otherwise it wouldn't be sipping power as it is. Again that is just how I see it and it isn't based off any actual experience :\ Just stuff I've observed over the years.

Also
HT = HT-Link and HTT = Base Clock


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## cadaveca (Jul 8, 2010)

Formula350 said:


> Makes sense, but wouldn't really cranking up the CPU PLL (which is the same as your LLC) allow for more stable power?


Nope. That 2.5v is stepped down from 12v, and as such, has a hard limitation.




> I mean yes this thing is only a 5+1 design, but it amazes me that I can have a chip that will operate overclocked 500mhz on such minimal voltage, that at any higher voltage it simply won't increase it's headroom.



Increasing voltage doesn't increase power delivery. If the power section can only deliver 150w, it can do that @ 100a @ 1.5v, or 115a @ 1.32v. Increasing voltage allows for a greater margin between the recognition of 1's and 0's, and trying to keep that ratio in a specific zone after current use makes it drop.




> After all (and this is an arbitrary current value) if a CPU is being fed the max a board will allow of 8A at 1.334v, the CPU is consuming 10.672W. Now feed that same maxed out 8A with 1.55v and it has 12.4W.



The only problem with looking at it that way us that when I speak of current limitations, I mean, really, wattage. It's not an arbitrary number that a board can deliver, when it comes to wattage, so maybe my terminogoly needs to change here.




> Under the conditions I'm at, it would seem to me that the CPU is not maxed out for clock, otherwise it wouldn't be sipping power as it is. Again that is just how I see it and it isn't based off any actual experience :\ Just stuff I've observed over the years.



it hasn't been long that we have had board support for 140w cpus, even. that means, no matter what voltage, you've got max only 140w to play with...not to say that's what you are limited to in this case, but I'll bet the board doesn't deliver much more than that.

This is why alot of people currently run into hard walls, and no voltage increase will seem to overcome that wall...voltage isn't always the answer.

When we do hear of cpus dying nowadays, it's from the high-end boards that have very purposefully removed those current limitations. When it comes to the newest chips from either side, and having Turbo, which is based on a hard wattage limit, you can bet this may just become even more of an issue than it ever has been...if the max the cpu design allows for, with turbo, is 125w, there's no need to build boards with more, when cost effectiveness is the ultimate goal for the company building the boards.


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## Formula350 (Jul 8, 2010)

cadaveca said:


> Nope. That 2.5v is stepped down from 12v, and as such, has a hard limitation.
> 
> Increasing voltage doesn't increase power delivery. If the power section can only deliver 150w, it can do that @ 100a @ 1.5v, or 115a @ 1.32v. Increasing voltage allows for a greater margin between the recognition of 1's and 0's, and trying to keep that ratio in a specific zone after current use makes it drop.



Gotcha 



> The only problem with looking at it that way us that when I speak of current limitations, I mean, really, wattage. It's not an arbitrary number that a board can deliver, when it comes to wattage, so maybe my terminogoly needs to change here.



What I meant by arbitrary, is what I had said with my example. I just pulled 8A out of thin air and I have no clue if that is at all what the CPU gets. My guess was more along the lines of 125W / 1.334v so 93.7A. Which if I'm understanding you right, and that IS the correct amperage, is then the maximum it can pull.




> it hasn't been long that we have had board support for 140w cpus, even. that means, no matter what voltage, you've got max only 140w to play with...not to say that's what you are limited to in this case, but I'll bet the board doesn't deliver much more than that.
> 
> This is why alot of people currently run into hard walls, and no voltage increase will seem to overcome that wall...voltage isn't always the answer.
> 
> When we do hear of cpus dying nowadays, it's from the high-end boards that have very purposefully removed those current limitations. When it comes to the newest chips from either side, and having Turbo, which is based on a hard wattage limit, you can bet this may just become even more of an issue than it ever has been...if the max the cpu design allows for, with turbo, is 125w, there's no need to build boards with more, when cost effectiveness is the ultimate goal for the company building the boards.



I figure that is how cdawall is able to get the overclocks he can, as I believe he uses a 790FX and I would figure it would have much more headroom for overclocking. 

Would it be a fair assumption that it is why most of the higher end boards run a larger power phase for the CPU? Like 10+2 as apposed to my 5+1, which the extra 5 on the CPU is due to the removal of the limitation you mention. 

Oh well I'm thinking about getting an 890FX, so we'll see then


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## Formula350 (Jul 13, 2010)

Well a little update: After what Cad had said about the Current Limiter, I decided to crank up the core voltage some more. I almost had 3.9GHz stable with 1.56v, it would puke on the AOD stability test, and it wouldn't boot Windows if I tried to start @ 3.9GHz. If I did it through Windows though it was OK. Seemed like 3.8GHz at 1.52v was stable, but I've been having a few random BSODs today. Yesterday I didn't have _any_ and I even played Mechwarrior 2 in DOSBox for a couple hours with no issues... I think most of the problems I was having was with turning on AHCI for IDE (which I believe isn't technically a feature of IDE but I think Gigabyte added IDE via an onboard IDE->SATA converter), though even after I turned it off I have had some random restarts. I do mean random, I wasn't even at the computer anymore and it restarted lol 

I'm sure I'll have to post this in the OC section for more responses, but I feel as if my issues with overclocking might come from my lack of knowledge with the voltages. The CPU-NB, CPU PLL, NB PLL, and then sort of the NB as well... I'll start with the last one first, what I don't get is if the CPU-NB and HT overclocks are affected at all by the NB voltage. Then when I read reviews of BE CPUs being OCed by multiplier, they don't mention any other voltage changes, so when they adjust just the core voltage and multiplier, is that _really_ all that is getting changed to manage the clocks they do? As for the PLLs, I have a bit of an idea on their importance, but it really isn't enough IMO to exactly help me overclock 

Oh I just remembered that 3.8GHz might actually be stable after all, as I just remembered I was running the DDR3 at 6-6-6-27  I didn't think about that till now which might be the cause of that random reboot, so it probably just need a couple mV more than what I have it at (default 1.9v) to be stable.

As of the 14th I'll be gone till the 10th, so sadly I won't be able to tinker  But it's a time for fishing, not computers, even if I do spend a lot of time on the laptop if we aren't catching anything 

I appreciate all the info BTW, as like I've said, I'm not all that up on current overclocking tricks. I can only apply what I previously knew and that only gets me so far heh


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## cadaveca (Jul 13, 2010)

OK. So, we have 2.5v pll to cpu, and 1.8v pll to SB. But hey, aren't they linked together by ACC?

Yes, they are, and that's exactly what "ACC" does...switches that 2.5v down to 1.8v!



So if you increase CPU PLL, you may want to consider also increasing SB pll to match.You should also be able to figure out how the ACC offset needs to be tweaked...up to 12% either way plus or minus...


cpu/NB is memory controller.

NB is chip on mobo.

They use thier own connection to communicate, called A-Link Express II. Default NB volts is 1.1v, and southbridge is 1.2v.

So, all the voltages on your mobo are related to one another, and all of them have tolerances that must be kept in check. If you increase volts in one place, you may just want to consider upping hte other voltages to match.


Now, CDA gets good clocks because of good boards, good mem, and *exceptional cooling*. Because chips leak current, cooling makes these leakages smaller, allowing for more of that current to be put to good use.


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## Corduroy_Jr (Jul 13, 2010)

Formula350 said:


> Gotcha
> 
> 
> 
> ...



correction higher end is 8+2 or 8+1 lower end 4+1


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## Formula350 (Jul 13, 2010)

Corduroy_Jr said:


> correction higher end is 8+2 or 8+1 lower end 4+1



Ohhh cut me some slack, it was like 3AM!


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## Formula350 (Jul 13, 2010)

cadaveca said:


> OK. So, we have 2.5v pll to cpu, and 1.8v pll to SB. But hey, aren't they linked together by ACC?
> 
> Yes, they are, and that's exactly what "ACC" does...switches that 2.5v down to 1.8v!
> 
> ...



Apparently we aren't _quite_ on the same page :\ 

To start: I have an 890GX+SB850, which means the NB voltage is not 1.1v but 1.3v. It also means that I have no ACC control  So I sadly can't tweak the settings to gain overclocks and specific core unlocks. I've been _trying_ to talk with the Gigabyte support on changing how some of the BIOS settings are shown, but I'm not really getting anywhere with who I'm talking with. I'm sure a little bit is language barrier, but it seems like most is due to the person not knowing anything and replying with scripted responses  If I could just get the Core Control options visible all the time, I could try and instruct the BIOS on which cores to attempt unlocking, instead of just trying to unlock every available core... Sadly neither my conversation with the tech support, or my attempts to modify the BIOS, have gotten me anywhere 

Now onto the other parts: I don't have any SB voltage options in my BIOS, and that very well could be the reason for why I can't OC, but since I don't have any knowledge/experience with the AM2/AM3 systems it is just a guess. Here is the list of voltage options (verbatim) I have in the order they are listed in the BIOS, their voltages (default is bold) and color reflecting how the BIOS depicts their safety. Bold red = what is darker red and flashing in the BIOS. Then Green is what I have it set at for CPU-3.7GHz, NB-2.4GHz, HT-2.4GHz, DDR3-1600 6-6-6-27



CPU PLL Voltage Control 
*2.500v*
,  2.220-2.660, 
2.70-2.860
, 
*2.900-3.100*
2.620

DRAM Voltage control 
*1.500v*
, 1.275-1.635, 
1.650-1.785
, 
*1.800-2.445*
1.995

DDR VTT Voltage Control
*¹*
*0.750*
, 9.720-0.875, 
0.900-1.125
, 
*1.050*

NB Voltage Control 
*1.300v*
 1.100-1.400, 
1.420-1.500
, 
*1.520-1.600*
1.460

SidePort Mem Volt Control 
*1.600v*
, 1.370-1.700, 
1.710-1.750
, 
*1.760-1.800*
 (IGP Disabled)
NB/PCIe/PLL Voltage Contro[sic]  
*1.800v*
, 1.450-1.890, 
1.900-1.990
, 
*2.000-2.100*
1.890

CPU NB VID Control
*² ³*
 1.175v  
_-0.600 to -0.025_
, +0.025 to +0.375, 
+0.400 to +0.600
+0.100 = 1.275v

CPU Voltage Control
*²*
 1.275v 
(Again CPU dependent and in +/-)
_-0.600 to -0.025_
, +0.025 to +0.375, 
+0.400 to +0.600
+0.100 = 1.375v

Normal CPU Vcore (Just shows the default voltage, not an actual option)
* 1.275v**¹* Grayed out when "DRAM Voltage control" is set to anything other than "normal"[default]
*²* Then this is applied or subtracted from the default
*³* (CPU dependent, the 250u was 1.050v)

So if CPU-NB *is* the memory controller (what is so hard about labeling it that? ), how important is it in relation to the memory overclocks? Or if it isn't actually the IMC, what impact does it have on the CPU overclocks? I also don't understand the DDR VTT either :\ Especially since it becomes unavailable when the DRAM V is changed, which in my case I _have_ to in order to run DDR3-1600 as OCZ recommends a default of 1.9v instead of 1.5v

Then the last part, I admit I might not have the ideal motherboard to overclock on. I do feel that my memory is not exactly bad stuff though  The cooling on the CPU is I feel more than adequate, if you go off of FrostyTech.com.  So while I can't say one way or the other on if my memory is indeed good stuff, I'm pretty sure I am covered in the CPU cooling department. 

Hopefully that can clear some stuff up


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## Corduroy_Jr (Jul 13, 2010)

hears what i would set
CPU PLL Voltage 2.8v
DRAM Voltage control 1.8v
DDR VTT Voltage Control don't worry about this options leave at auto
NB Voltage Control default is 1.2 leave at auto
SidePort Mem Volt Control auto
NB/PCIe/PLL Voltage Control not 100^ sure on this one, but its not need set to auto
CPU NB VID Control this is the actual voltage for north bridge set to 1.25v if aiming for 2600mhz
Normal CPU Vcore set to 1.35v if aiming for 3.8ghz, 1.45v or a tad higher if aiming for 4ghz
one thing Ive noticed that's missing is ht voltage?
and last theirs no south bridge voltage? not a big deal
also lower memory divider to lowest setting set all timing manual relaxed 
lower nb multiplier along with ht
just work on cpu only to find max clock


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## cadaveca (Jul 13, 2010)

Formula350 said:


> So if CPU-NB *is* the memory controller (what is so hard about labeling it that? ), how important is it in relation to the memory overclocks? Or if it isn't actually the IMC, what impact does it have on the CPU overclocks? I also don't understand the DDR VTT either :\ Especially since it becomes unavailable when the DRAM V is changed, which in my case I _have_ to in order to run DDR3-1600 as OCZ recommends a default of 1.9v instead of 1.5v





Ok, so, for me, cpu/NB makes very little difference for clocking, except when increasing cpu-NB overall speed, or when getting close to the limits of the controller. Although default is typically 1.15 or 1.175, I can run 1.1v no problem up to 1750mhz or so.

But, as I increase mem voltage above 1.5v, cpu/nb needs to be higher to retain long-term stability.

Likewise, DDRVTT is a direct ratio of vDIMM, and should be set to 1/2 of vDIMM. To explain a bit, the vDIMM would be like a 1, and the VTT voltage would be a 0.

Your NB voltage is a bit higher due to having IGP. That said, I really find it odd that you need to icnrease PLL voltages at all, so, if possible, try running them @ stock. If you find it's really neccesary, then you might want to consider saving yourself some time, and go with the best you got now.


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## Formula350 (Jul 13, 2010)

Corduroy_Jr]hears what i would set
CPU PLL Voltage 2.8v
DRAM Voltage control 1.8v
DDR VTT Voltage Control don't worry about this options leave at auto
NB Voltage Control default is 1.2 leave at auto
SidePort Mem Volt Control auto
NB/PCIe/PLL Voltage Control not 100^ sure on this one said:


> Ok, so, for me, cpu/NB makes very little difference for clocking, except when increasing cpu-NB overall speed, or when getting close to the limits of the controller. Although default is typically 1.15 or 1.175, I can run 1.1v no problem up to 1750mhz or so.
> 
> But, as I increase mem voltage above 1.5v, cpu/nb needs to be higher to retain long-term stability.
> 
> ...



When you say 1750MHz, are you talking about DDR3 speed or the CPU NB speed? And if you are referring to the CPU NB speed, then are you meaning 2750MHz and it was just a typo?

Since my memory _requires_ 1.9v (as per the sticker) for DDR3-1600 7-7-7, is it necessary for the CPU-NB to be bumped up? I mean if I were to drop everything back to default and find the system is stable after an overnight burn, you think that upping it would improve the overclocability of any of the other components?

And the DDR VTT really is of no matter, since I can't change it. However if I set it to 0.95v, would the BIOS then set the DRAM voltage to 1.9v as a result? Also your explination makes sense given the default voltage of DRAM is 1.5v with the DDR VTT coming in at 0.750, but you math is wrong in your example  1v would have a VTT of 0.5v, not 0v 

And yea I'm trying to get the voltages down to try and find lowest stable setting. The two reasons I'm trying for more is that CDA was able to reach 4GHz stable and 4.2GHz bootable on this CPU, and when I had the Athlon II in here I was able to just clock the hell out of the CPU-NB, HT *AND* HTT. While you've made valid points in relation to the first one, I don't see why the HT can't go higher, but what I find more confusing is why the HTT (base clock) is over 135MHz lower limit with the PhII  If someone could explain why it is I'd be comfortable with it, but as I can't find a reason for it that makes me want to be able to achieve it again, you know?


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## cadaveca (Jul 13, 2010)

with vtt, when I said 1 and 0, i mean in binary data...the vdimm would give a value of one, the ddr VTT signal(low point in ddr voltage wave) would be 0...not in volts...changing ddr vtt changes where the low value is "noticed" as valid data.

1750mhz is DDR speed.







Bios doesn't change the values...that's up to you. They are only really responsible for stock operation, and if it was set appropriately, then there'd be no need for that to be user adjustable, as on many other boards. They've left it there as an option for a reason...


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## Formula350 (Jul 13, 2010)

cadaveca said:


> with vtt, when I said 1 and 0, i mean in binary data...the vdimm would give a value of one, the ddr VTT signal(low point in ddr voltage wave) would be 0...not in volts...changing ddr vtt changes where the low value is "noticed" as valid data.
> 
> 1750mhz is DDR speed.
> 
> ...



Ah ok, gotcha heh Makes sense then 

And your screen shot isn't 1750Mhz  802.7MHz is 1605.4MHz  The highest stable I have managed with mine, which I can't remember exactly what the settings I used anymore, was 1800MHz. I think I had used either 7-8-7 2T or 8-8-8 2T, with around 2.05v for the memoy. 

I finally found a stable operating configuration for 3.7GHz/2.4GHz/2.4GHz with DDR3-1600 @ 6-6-6 1T. As I mentioned in the last post, I was dropping voltages down and noticing increased stability test length before it would fail. 
CPU: ~1.375v  (I think, might be 1.35v)
CPU-NB: 1.3v (possibly 1.275v)
NB/PCIe/PLL ("VCC" in AOD): 1.83v
DRAM: 1.95v (had to drop it down from 2v)
CPU PLL ("VDDA" in AOD): 2.54v (down from ~2.8v)
NB Core: 1.44v (down from 1.46v)

Right now I'm testing one core @ 3.8GHz, the other @ 3.7GHz with 1.46v on the core. Only reason I bumped it up so much higher is just to make sure. Once I find out it is stable, I'll bump the other core's multi and see if both @ 3.8GHz is stable. If so, I'll attempt 3.9 on one, rinse repeat. So far it's been 13mins stable with 3.8/3.7 @ 1.46v, which before with higher voltage I couldn't get a single one stable near this long at even 1.5v  

I R LURNENG STUFS!!!11  Or well maybe not _learning_, but figuring it out and I can convert it to knowledge later!

DOH just looked back and the 30min Stability Test failed on 3.8/3.7 after 14mins  I was hopeful too! Back to the grind I guess heh


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## Corduroy_Jr (Jul 13, 2010)

maybe this will help
my PII 955BE x4 turned into a PII 555BE x2
to give u a summary of settings i had set in bios to reach 3.8ghz. actually it was quite easy after words i pushed farther 4.2ghz 1.5150v 

Cpu speed 3808mhz
Fsb 238
Cpu multiplier x16
Cpu vcore 1.30v stock is 1.350v
Cpu_nb 1.20v 2619mhz multi x11 (stock is 1.750v)
Stock ht 1.20v 2380mhz multi x10
Dram voltage 2.1v
Memory divider 12/6
Memory speed 952mhz 5.5.5.10 2T


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## Corduroy_Jr (Jul 13, 2010)

with all four core i pretty much reach the same clocks with a tad more volts
Cpu speed 3808mhz for the big 4.0 i need 1.48250v
Fsb 238
Cpu multiplier x16
Cpu vcore 1.36250v
Cpu_nb 1.20v 2619mhz multi x11 (stock is 1.750v)
Stock ht 1.20v 2380mhz multi x10
Dram voltage 2.1v
Memory divider 12/6
Memory speed 952mhz 5.5.5.10 2T


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## cadaveca (Jul 13, 2010)

Formula350 said:


> Ah ok, gotcha heh Makes sense then
> 
> And your screen shot isn't 1750Mhz  802.7MHz is 1605.4MHz



Yeah, just an example of voltages that can be used, I'm actually playing around with cpu @ 3.4ghz, and trying to find lowest voltage that it will work with. That's 800mhz @ 1.5v vDIMM, 1.1vNB, and CAS7. I just wanted to show 800mhz/2400 with low vDIMM and cpu/NB volts.

My ram will do 800mhz CAS 7 @ 1.35v...but my board doesn't go lower than 1.5v.  It's 8GB though, so does place a signifigangt load on the NB...I can't get CAS7 900mhz stable, even, with 4 sticks, but I can mix and match any two for 900mhz CAS6 !



> The highest stable I have managed with mine, which I can't remember exactly what the settings I used anymore, was 1800MHz. I think I had used either 7-8-7 2T or 8-8-8 2T, with around 2.05v for the memoy.



just over 900mhz(1800) there is a hard wall on Phenom2. each chip will do a bit differently over 900mhz, some just barely reaching, others will go higher. I can just barely reach 1990. AMD recommends to not go over 2.1v for DDR volts, FYI.



> I finally found a stable operating configuration for 3.7GHz/2.4GHz/2.4GHz with DDR3-1600 @ 6-6-6 1T. As I mentioned in the last post, I was dropping voltages down and noticing increased stability test length before it would fail.
> CPU: ~1.375v  (I think, might be 1.35v)
> CPU-NB: 1.3v (possibly 1.275v)
> NB/PCIe/PLL ("VCC" in AOD): 1.83v
> ...


try CAS7, and see how low you can push you ram volts. you'll lose about 1GB/sec bandwidth in benches, but I find that around 9GB/sec or so is OK for 24/7 stuff and gaming, just not benching.


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## Formula350 (Jul 13, 2010)

Corduroy_Jr said:


> maybe this will help
> my PII 955BE x4 turned into a PII 555BE x2
> to give u a summary of settings i had set in bios to reach 3.8ghz. actually it was quite easy after words i pushed farther 4.2ghz 1.5150v
> 
> ...




While I _have_ been thinking of making a thread in the OC section where people will post up their overclocks and the settings/voltages used to attain them, sadly I am not finding much help from yours  Since yours already was an x4, it's a decent bet it was a better core to start with (given CDA wasn't able to unlock mine to x4), so pair that with the fact you can down volt to reach 3.8GHz doesn't make things better for me lol Isn't your 955 default speed 3.4GHz anyways?

Similarly you are running what appears to be a 790 chip from the DDR2 days (based on timings), so I wouldn't be able to really apply those settings to my system given it's an 890GX (785G for all intents and purposes) with DDR3 

I appreciate the info anyways though!

Right now I'm trying to do one of only like 3 things I can do w/o having to restart and change things in the BIOS. I'm attempting 3.8GHz on one core with the other at only 2.1GHz, to see if that helps stability. Then if not I'll drop the NB and HT down as low as I can and retry...


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## cadaveca (Jul 13, 2010)

Hmm...maybe you'd like this(from AMD document)?


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## Corduroy_Jr (Jul 13, 2010)

only thing is different is dd2 to dd3 everything else is the same concept although some motherboards have more voltage option's then others and also named them differently, and yeah its a Ati 785gx chipset, maybe i got a cherry chip who knows lol, 

good luck as i always say happy tweaking lmo


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## Corduroy_Jr (Jul 13, 2010)

cadaveca said:


> Hmm...maybe you'd like this(from AMD document)?
> 
> http://forums.techpowerup.com/attachment.php?attachmentid=36927&stc=1&d=1279055714



nice good find


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## Formula350 (Jul 13, 2010)

cadaveca said:


> Yeah, just an example of voltages that can be used, I'm actually playing around with cpu @ 3.4ghz, and trying to find lowest voltage that it will work with. That's 800mhz @ 1.5v vDIMM, 1.1vNB, and CAS7. I just wanted to show 800mhz/2400 with low vDIMM and cpu/NB volts.
> 
> My ram will do 800mhz CAS 7 @ 1.35v...but my board doesn't go lower than 1.5v.  It's 8GB though, so does place a signifigangt load on the NB...I can't get CAS7 900mhz stable, even, with 4 sticks, but I can mix and match any two for 900mhz CAS6 !
> 
> ...




Well I've tried a few things so far, dropped the memory as low as possible with what the BIOS has provided (lower DDR settings are in there, but hidden ) and while I don't exactly remember the voltage, I believe 1066 was fine @ 5-5-5 1T lol I think I actually had it only like 1.6 or 1.7v. I believe I was able to get 1333 out of 1.5v with 7-7-7, but since I've been changing settings so much, with not one thing really being a constant, I'm just unsure lol

If I had Sandra setup I could see what my 6-6-6 results in, but I don't expect it to gain me 1GB/s. That would mean almost 14gb/s I think

Why does the actual DDR voltage matter to the CPU? I mean if AMD doesn't recommend higher than 2.1v, and the actual IMC is far from being that, what impact does the DDR3's voltage make? Again I ask because I seriously don't know lol 

My 3.8/2.1 test failed initially. I've moved up the 2.54v up to 2.58v, and 1.83v up to 1.84v, so far the re-test is progressing fine after 15mins. Since it is time consuming enough, I've only got it set to run for 30mins. I suppose I should probably just run IntelBurnTest, as it usually does as good a job, but will find stability issues in a much shorter period of time....




cadaveca said:


> Hmm...maybe you'd like this(from AMD document)?
> 
> http://forums.techpowerup.com/attachment.php?attachmentid=36927&stc=1&d=1279055714



Tis an interesting bit of info, but still leads to further confusion given with the 250u I was easily pulling off 2.9GHz on air, which was before I had this awesome cooler I have now! All I was using then was a stock all aluminum S939 cooler lol 

I think (only a guess based off the pic) that the DDR3 voltage they are referring to is the "VCC 1.8", what my BIOS calls the NB/PCIe/PLL, which I think the picture is implying the memory controller voltage...


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## cadaveca (Jul 13, 2010)

I like iBT because you can load up all the ram while it tests. But Prime95 offers that as well.

I've been doing iBT, Prime, then some games, and it seems to work good.

Take a look at the maxxmem thread for a general idea of what people are getting memory-wise.

I think DDR3 in the high end really pushes the limits of the controller, so is more sensitive in DDR3 mode. I mean really...1.65vCAS8 is pretty cheap right now. Supporting older DIMMs isn't something they had to do...I don't think Intel officially supports 1.8v or higher DIMMs on i5/i7, nor do they offer to use both types of ram, so I jsut figure that some concessionsions were made in order to keep the cost down for those upgrading...

Kinda odd about the PLL volts, but maybe that's just the cpu.


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## Zen_ (Jul 14, 2010)

Formula350 said:


> I almost had 3.9GHz stable with 1.56v, it would puke on the AOD stability test, and it wouldn't boot Windows if I tried to start @ 3.9GHz. If I did it through Windows though it was OK.



To my knowledge lower core temps yield a higher overclock potential with Phenom II's than higher voltages. For example, 4 GHz with 1.5v @ 56C may be unstable, but 4 GHz with 1.42v @ 51C may be perfectly stable with a full linpack load. On my own system I top out @ 3.83 GHz stable linpack no matter what voltages or bus speed I run. I mention this because it seems like you're running a rather high core voltage. 

That was something I didn't quite understand coming from a C2D setup that was essentially run as much voltage and heat as you dared for the maximum stable overclock.


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## Formula350 (Jul 14, 2010)

Zen_ said:


> To my knowledge lower core temps yield a higher overclock potential with Phenom II's than higher voltages. For example, 4 GHz with 1.5v @ 56C may be unstable, but 4 GHz with 1.42v @ 51C may be perfectly stable with a full linpack load. On my own system I top out @ 3.83 GHz stable linpack no matter what voltages or bus speed I run. I mention this because it seems like you're running a rather high core voltage.
> 
> That was something I didn't quite understand coming from a C2D setup that was essentially run as much voltage and heat as you dared for the maximum stable overclock.



Right, and I fully understand that too. Heat raises resistance and resistance causes heat, so it's a bit of catch 22. Still I am not seeing over 46c at 1.55v, so I don't think heat is my issue :\ Which is just _another_ thing that adds to my confusion  

To _me_, a CPU that can run at relatively low voltage when overclocked (1.33v is what I typical run at 3.7GHz with not having tried much lower yet) and a heatsink capable of cooling it very well, makes me think the CPU will yield very nice OCs! And not to beat a dead horse, but especially given that cdawall was able to get 4GHz out of it. Which I do understand the importance of the motherboard's power capabilities, but I just can't imagine that my board would be lacking that much :\

*shrug* It will have to wait, as I need to finish packing and get ready for a 12hrs of travel, not counting the 4hr time difference! Plus the fact it doesn't get dark till about 1am, but after 27 years I'm a bit used to that 

Thanks for all the help, and I'll still check in on the thread as long as I can while I'm at the cabin, provided my neighbor's have WiFi still


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