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ASRock 939Dual-SATA2 VCore & VDIMM Mod

Hi, I just posted this at another site, but I guess it'd be better to post it here, since the maker of the mods actually reads here (thanks for the Radeon 9500 work btw W1zzard) >)

It's only an idea, and some members here will probably be able to poke a, or multiple hole(s) into this, but here goes.

This is about the VDIMM mod that tells you that if you connect a certain solderblob to another solderpoint, you'll feed 3.2V directly into your memory, alternatively, you can run the 3.3v line from your PSU into it to get 3.3v.

First off, are there any problems with this method? How does it work, does it override the bios voltage? Cuz I can't imagine it Adding that voltage to the existing flow >P

Anyhoo, if there's nothing wrong with that mod, how about taking a molex's 5v line (or a certain ATX motherboard plug pin?), putting a quality adjustable resistor between it, and running that into said solderpoint?
Theoretically you should be able to give it any voltage you want then, kinda like high-end DFI boards take their VDIMM from the 5v line.
Handy for people with BH5 memorysticks, cuz those can need upto, say, 3.6v with active cooling?

Just be really sure to measure it beforehand and during >P

Anyway, this is just an idea for now, I can't test it cuz I don't have my board, and since Opterons are really hard to get at the moment, I'm gonna have to wait quite a while for my setup to arrive :(
So please, don't anyone who isn't sure try this, I'm so far just wondering what the more knowledgable people here think of the idea.
 
if you feed a higher voltage directly to the memory, the original voltage regulator on the mobo will see "oh i'm too high on voltage" and reduce its output.. but it's still too high.. so it should completely turn off and finally your cable will supply the whole memory voltage.

the problem about "quality adjustable resistors" is that i am pretty sure you will have a hard time finding one with the wattage you need. Remember, the excess voltage has to be dissipated as heat in the resistor.
 
W1zzard said:
if you feed a higher voltage directly to the memory, the original voltage regulator on the mobo will see "oh i'm too high on voltage" and reduce its output.. but it's still too high.. so it should completely turn off and finally your cable will supply the whole memory voltage.

the problem about "quality adjustable resistors" is that i am pretty sure you will have a hard time finding one with the wattage you need. Remember, the excess voltage has to be dissipated as heat in the resistor.
Click to expand...

Alright, so I won't burn anything up over time hopefully ;)

hmm, well, they've been able to integrate such a solution on the DFI boards, so I guess there Should be ways powerful enough (well, at least on the DFI Expert boards, heard the earlier implementation had some problems).
Do you have any ideas on it? Maybe multiple chained together, or some sort of circuitry to clean it up and lower it.

What kinda wattage would be needed for something like this?

Or, maybe a bit more far-fetched, something liking to the 7v solution for fans, 12v+5v line = 7v ? (lowering some other powersource on the board \ a PSU plug with a resister and running that against the 5v line you feed into the RAM somehow?)
 
let's take the 3.5A from the article (this might not be 100% accurate, but a good ballpark figure)

5V input, 3.5V output -> 1.5V drop needed..

3.5A * 1.5V = 5.25W .. sounds a bit low to me .. better look for 8W+ which probably means you need some kind of active cooling for the resistor
 
W1zzard said:
let's take the 3.5A from the article (this might not be 100% accurate, but a good ballpark figure)

5V input, 3.5V output -> 1.5V drop needed..

3.5A * 1.5V = 5.25W .. sounds a bit low to me .. better look for 8W+ which probably means you need some kind of active cooling for the resistor
Click to expand...

Alright, but, saying I'd be able to get a resistor like that, running that 3.5v into that solderpoint would work, right?

The countervolting idea seems like insanity to you I take it, since you didn't touch on it? ;D

Also, say I chain 3 standard adjustable resistors in a row, let each take care of say 0.5 volt, would that be cleaner and take most of the pressure off of them? Say, make it actually feasible? >)
How much can a standard (what's standard anyway, 1000ohm? I'm lacking in knowledge here :/ ) adjustable resistor be expected to take for the long run anyway?
 
typical resistors are 1/8 watt ..
 
W1zzard said:
typical resistors are 1/8 watt ..
Click to expand...

Eep >_<

so this is all to do with how much the RAM pulls from the powerline?
 
yep .. 1/8 watt resistor on the line to the memory -> little charred piece of ash after 1 second of pc on

*runs off to find resistor for demonstration*

before.jpg


after.jpg


video of resistor in action: http://www.techpowerup.com/img/05-12-01/resistor.mpg
 
Last edited:
W1zzard said:
yep .. 1/8 watt resistor on the line to the memory -> little charred piece of ash after 1 second of pc on

*runs off to find resistor for demonstration*
Click to expand...

lol, kick ass that you actually demonstrated it, nice flash, thanks >D
too bad, I thought the "big" adjustable ones were alot better than the small non adjustable ones :/
Makes me wonder what makes an OCZ Booster work then, thought that was just a thing shaped like a piece of RAM with a resistor hooked to your 5v line, guess I've got some homework to do still :)
 
ocz booster should work on that board afaik ..
 
W1zzard said:
ocz booster should work on that board afaik ..
Click to expand...

Yeah, should, I just like hacking something together better ;D
Ah well, must be some source somewhere on the internet describing how one works.

And I'll just visit the local hardware store to check if they have something strong enough.

Thanks for the help and info, good to know that some "giants" of modding are so easy to get in touch with :D
 
Well guys,

tnx 2 the help of the vcore mod, i'm proudly and able to present my (stable) oc:

CPU: Athlon 64 Venice 3200+(@2,0Ghz) --> 2,8 Ghz(10x280HTT) - 1,57v
Mem: Dane Elec 400ddr cl3 --> 466ddr 3-3-3-8-2T (ram:cpu - 5:6)
CPU-NB: 800Mhz (16bit)
NB-SB: 800Mhz (16bit)
Dram: High (2,7v)
Cool n Quit: Disabled
Spread Spec: Disabled
BootFailureGuard: Enabled
Fast Writes: Disabled

It cost me some time to find the exact settings. But it's definitely word it!
Hoop it stays stable, maybe i should get some spreaders voor my mem?
Dunno i'll see..

chears:toast: ,

Swah
 
The problem with this board and the OCZ booster is that if you want to run 2 sticks in DC you won't probably be able to use the ram booster as the DC pairs are right next to each other. The boosters need to be atleast one slot apart to fit in.
 
vpjansen said:
The problem with this board and the OCZ booster is that if you want to run 2 sticks in DC you won't probably be able to use the ram booster as the DC pairs are right next to each other. The boosters need to be atleast one slot apart to fit in.
Click to expand...

That's incorrect since i am currently running 2x512 in Dual Channel mode Dimms 3/4 along with the Booster in Dimm 2 running @ 3.4v for over three months now.
 
Any easy way to get 2.9v vdimm?

variable voltage mod would be perfect but is very difficult to me and my soldering skill
 
I made the Mods for my Asrock Dual but now I need to find out the voltage i'm giving to Ram, Made the "150 Ohm" mod... Need to know if there's a way to measure the voltage... Even with a multimeter I don't know where to use it... lol

Tks in advance
 
could you put a photo to see your work?

if i join those points
vdimm1.jpg
with a resistor can i get 2.9v?
 
Beats me!!! I did a different mod, not listed in this site...



Of course i asked for help on this... lol

I need to make sure it's working before instaling the more expensive TCCD... Anyone has a clue on how to measure the DRAM voltage?
 
measure voltage on pin 7 of the memory slots for ddr voltage
 
Thanks, if you find other ways specific to this board let me know ;)

PS: Couldn't take a picture of the Vcore mod with the motherboard mounted... Sorry
 
Jusat one glitch, if you put one of the multimeter's part in pin 7 where does the other one go? You'll have to close the circuit between the pins and the multimeter...

tks
 
I made this volage regulator circut for another mobo, but I'm going to try it.

I mounted it in a drive bay with a bracket I cut out of a old zip drive, used a molex spliter to power it off the 12v rail, and used a clasping probe to hook it to the MOS-FET that outputs Vdimm. My OCZ VX may need 3.6v.

With this you can use any voltage, cheak it with a DVM before connecting!
 

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Well try it... I'll have to excuse me, but thet thing looks insane in my point of view... Don't know if the circuits will hold 3.6V
 
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