How-to: Pencil mod your HD 3870!

[Random Murderer]

Do you think you could figure stuff out if I make hi-res pictures of the PCB?
I equipped my 3870 with a Zalman VF1000 yesterday, which dramatically dropped load temps by 12C with the fan on low and that's without taking thermal grease cure time into account...

Unfortunately, this didn't seem to improve my card's overclock capabilities. Volt modding must be the answer

Current results (yes, I have a small case, which affects GPU cooling capabilities):
Stock clock: 777/1126 @ 56C load
Stable max: 864/1168 @ 61C load

Previous results (stock cooler):
Stock clock: 777/1126 @ 68C load
Stable max: 864/1126 @ 74C load

I have a gut feeling this can be improved :shadedshu

your max oc has nothing to do with temps. the fact that you are maxing out at 864 tells me that your bios has the pll lock. update your bios to a newer version and i guarantee you will be pleasantly surprised.

 

[Thrackan]

your max oc has nothing to do with temps. the fact that you are maxing out at 864 tells me that your bios has the pll lock. update your bios to a newer version and i guarantee you will be pleasantly surprised.

I can clock it higher but it shows artifacs then. As far as I read I thought the 860 limit was a hard limit, as in you couldn't even try a higher setting, while I can.
But it can't hurt putting in a modded BIOS. Now if only the workday would end

As far as memory clocking potential is concerned, is this affected by a new BIOS as well?

Still, would you like high-res pictures of the ASUS board? Even if I won't mod it, it might be useful to others who will...
Getting a pic of the GPU side would mean I'd have to take the cooler off again though, I don't know if that's a useful side to picture? If so, I might do that too. Might need more thermal grease then though.

 

[Random Murderer]

I can clock it higher but it shows artifacs then. As far as I read I thought the 860 limit was a hard limit, as in you couldn't even try a higher setting, while I can.
But it can't hurt putting in a modded BIOS. Now if only the workday would end

As far as memory clocking potential is concerned, is this affected by a new BIOS as well?

Still, would you like high-res pictures of the ASUS board? Even if I won't mod it, it might be useful to others who will...
Getting a pic of the GPU side would mean I'd have to take the cooler off again though, I don't know if that's a useful side to picture? If so, I might do that too. Might need more thermal grease then though.

i never really got a thourough look at the asus 3870, but if it's like the 3650, the circuitry i'm looking for is on the gpu side. however, it could also end up being on the reverse side like the reference pcb, so i'll need both.

although it hasn't been proven, i believe the bios will have an effect on the mem oc as well.
if you could, would you mind running gpu-z and posting a screenshot so i can see your bios version, please?

 

[Thrackan]

Did a couple of nice things in the last couple of days:
- Overclocked to 891/1170 no-artifact stable (AtiTool tested for several hours)
- Flashed my motherboard dead and revived it again (Thanks Asus CrashFree!)
- Finally reflashed my V3-barebone motherboard to a full-featured P5K-VM bios so I can overclock my CPU
- Did some babysteps and got my E6750 up from 2,66 to 3,2Ghz in one attempt

All of the above brought my 3DMark06 score up to 11642 (stock was 10221) with great temps

I'll make some pictures of the card though, probably tomorrow. I'll give you the backside first though, I think it's a hassle to have to remove the cooler again

 

[Dr. Spankenstein]

Quite a nice list of accomplishments! Well done!

Enjoy the system you've "created" by not settling for "stock" performance!

Cheers!

 

[ivanka_13]

I can't seem to find an R1222 marked resistor on the PCB, I do see an SR122 one?

Full backside:

as for the Palit HD38xx PCB, we cant seem to find R1222 at the backside. Is there a possibility that we can locate it at the frontside? where the heatsink covers it?

 

[Thrackan]

I managed to snap one well-focused picture before my camera's batteries decided to say no...
Oh and the flash is ABSOLUTELY necessary when taking a pic inside a fully blue-lit system case

First look is quite different from what I've seen on other cards in this topic :shadedshu but I will get some more of the back when my batteries are recharged again.
Took a good peek, but nothing marked "R1222" on the backside either...

Offtopic: My CPU overclock was severely limited by my RAM. Might go out and get some quality DDR2-1066 sticks instead of the DDR2-800 "Value"RAM I have now

 

[Random Murderer]

thanks, but i'll need some more "head-on" shots so i can read the part numbers off of the ic's.

 

[Thrackan]

thanks, but i'll need some more "head-on" shots so i can read the part numbers off of the ic's.

Thought so, but at least I can say it's a pretty different layout. To the back end of the card, where the R1222 is located on the reference board, there is just a very small cluster of parts, nothing like reference layout.
Chances are big that the important parts are on the cooler side :shadedshu

 

[ivanka_13]

@Thrackan

maybe the R1222 is located at the frontside of the GPU, beneath the cooler.. The Asus PCB looks similarly the same w/ my Palit HD3870..

 

[Random Murderer]

@Thrackan

maybe the R1222 is located at the frontside of the GPU, beneath the cooler.. The Asus PCB looks similarly the same w/ my Palit HD3870..

right, but on a non reference board, r1222 could be for a completely different use than on a reference board.

 

[Thrackan]

Duh, I've been sick for a couple of days now, pretty annoying cold.
I prefer not to sneeze/cough/dribble inside my case and stuff, so new pics might take a while

 

[Random Murderer]

Duh, I've been sick for a couple of days now, pretty annoying cold.
I prefer not to sneeze/cough/dribble inside my case and stuff, so new pics might take a while

lol, no worries.

 

[ivanka_13]

On the Palit PCB, I cant seem to find the R1222 at the frontside, there are no labels of the components on the frontside but on the backside we seem can find a SR122.. can we verify this one if it's the same w/ the R1222 on the reference PCB..

 

[Random Murderer]

On the Palit PCB, I cant seem to find the R1222 at the frontside, there are no labels of the components on the frontside but on the backside we seem can find a SR122.. can we verify this one if it's the same w/ the R1222 on the reference PCB..

on non reference boards, the layout, part naming, and generally the entire card, is different.

 

[ivanka_13]

so? there will be no possibility to volt mod it?

 

[Random Murderer]

so? there will be no possibility to volt mod it?

there is a way. there must be.
unfortunately, nobody has bothered to figure it out as far as i know, and i would actually need the card in my possession to figure it out(or a schematic, but good luck finding and/or making one).

 

[Toxicologist]

Hi

I've got the same problem with my ASUS EAH 3870 TOP nonreference Card.
This Card, compared to the reference design, almost looks empty, because there is many empty space and lots of "stuff" (resistors etc) seems to be missing.
It even does not have this chip with legs to all four sites, which can bee seen on nearly every photo explaining a 3870 VoltMod (at least it's not on the backside ).
But now some more pictures, detailed enough to read the inscriptions of the parts

Picture 1
Picture 2
Picture 3

(are quite big, flatrate recommended )

If you need pictures from the upside, too, I could take some, but then I'd need to buy some new thermal grease at first to remount the cooler after photographing.

greetings
the Toxicologist

 

[Thrackan]

I've put the pencil mod idea in the cooler for now, since I've already got a casebuild to finish and an urge to silence my current "main rig".
Be sure to look out for a worklog someday.

 

[DanishDevil]

Hi

I've got the same problem with my ASUS EAH 3870 TOP nonreference Card.
This Card, compared to the reference design, almost looks empty, because there is many empty space and lots of "stuff" (resistors etc) seems to be missing.
It even does not have this chip with legs to all four sites, which can bee seen on nearly every photo explaining a 3870 VoltMod (at least it's not on the backside ).
But now some more pictures, detailed enough to read the inscriptions of the parts

Picture 1
Picture 2
Picture 3

(are quite big, flatrate recommended )

If you need pictures from the upside, too, I could take some, but then I'd need to buy some new thermal grease at first to remount the cooler after photographing.

greetings
the Toxicologist

I'm no expert on this stuff, but with the back of the card looking like that, I'm guessing you're going to have to post some pictures of the front of the card in order for RM to figure it out (if he can). Some fresh thermal paste (over the stock one especially) wouldn't hurt

 

[Random Murderer]

I'm no expert on this stuff, but with the back of the card looking like that, I'm guessing you're going to have to post some pictures of the front of the card in order for RM to figure it out (if he can). Some fresh thermal paste (over the stock one especially) wouldn't hurt

exactly.

 

[Dark-Link]

Hey guys! Hi!

First of all, I must say that my English is not good. Sorry ...

Ok, lets begin...

Yesterday I started to read the thread just for curiosity. Today I finished reading the thread and started with the pencilmod.

I have a MSI RX3850 OC 256Mb Edition (Core 690Mhz). PCB Layout its not exactly the reference, dont have the points to measure vcore in the 90% of pics posted. Rest of layout its the same

My results were mediocre, but equally Im happy!

I made the pencilmod to R1222 resistance, leaving it in 1.9KOhm. I did not do it more because I could not measure the Vcore (I do not know precisely how to do it )

Core: 690Mhz -> 796Mhz

Thank you so much everyone!

Greetings

 

[DanishDevil]

Nice! If you can't currently measure the vCore, just keep an eye on your temps!

It was a long read, wasn't it? But it was worth it!

 

[Dark-Link]

Nice! If you can't currently measure the vCore, just keep an eye on your temps!

It was a long read, wasn't it? But it was worth it!

Yeah! it was LOOOOOOOOOOooooooonnnnng!!!


My temperatures are around 90ºC full load (20mins in FurMark) . In-game (FarCry2/GRID) are around 73ºC in the same time.

See ya!

 

[DanishDevil]

That's getting warm, but it's fine. Just don't expect to get more than 2 or 3 solid years out of it...you may not.