FX5900XT Vmod, anyone?

[TodB]

Is there somebody with a FX5900XT that knows the Vmods?

In particular those with the Intersil ISL6522..... I got one Gigabyte FX5900XT, using two ISL6522.... I think for both memory and GPU...

Any info? at least what pot range? 200k, 100k, 50k?

[TodB]

Not a single person with a Vmodded 5900XT?!?

[Garrett]

http://www.ocforums.com/archive/thread/267604-1.html
This is an interesting thread of a guy who obviously vmodded his 5900XT and he did even manage to fry his card in the process

The vmod on the GPU is on the ISL chip. Pin 5 to ground. At 15K Ohms the voltage increases from the stock setting of 1.45 to 1.5v. Ran it up to 7.54K Ohms and got 1.55v. This allowed me to bench at 525/976 on 2001 and 520/976 on 2003. Cooling has still not been modded as of yet so I did not take it any farther. Ran the mod on the 6012 chip however got heavy artifacting even though it would run up to 525/1009. This indicates to me (at least as of this time) that the ram is not up to the task of running at those speeds. Without the vmod with the card at 525/990 it would kick down to the slower speeds seen in 2D. For now 976 will have to suffice and I will not leave the 6012 mod in place. Now for the results.

Ran the voltage up to 1.65v on the GPU. This achieved 535/976. Not bad for the 5900XT. Brought up 2003 and started running it. Scores where looking really good however I was somewhat alarmed when about half way through the artifact free run, there was a spectacular ball of flame and sparks that came from the vid card. We are talking a rather large ball of fire. Really brightened up the room it did. One of the benefits of testing at night is the spectacular fire works show. For those unaware, this really is not a desired effect. I now have a very burned, eight leg chip (id unknown due to the numbers being burned off), located next to the ram, towards the end of the card on the front side. Seems that though the GPU can handle the voltage, there appears to be a circuit that can not on the 5900xt. Too bad as the in the first test, when the fighter is firing, the fps got up to 1,000. Would have been a good run however it needed to complete it without frying the card.

At any rate no further damage done to the computer and presently have a backup 4200 in it.

I hope this helps you, and me too, because yes, I'm looking for a GPU Vmod too for my Club3D 5900XT

[Mod_Aap]

Here it is:
http://www.ocforums.com/vb/vb/showth...highlight=volt
Have fun

[Garrett]

http://www.ocforums.com/showthread.p...97#post2495997 is the "original" thread on the pieces I quoted, correct me if I'm wrong

[TodB]

Well that info is something, but...... not enough... that guy says some, but I need more info.... measuring points, etc...

Send him a PM, we'll see...

[Hud stromar]

I'm looking for that Volt mod too.

Here are some pictures of the card, how it looks
Front:


Back:


I think that all the important IC's are marked with red numbers.

IIRC the nuber 1 and 2 on the back of the card are Intersil's ISL6522

If anybody knows more than I do, the help would be more than welcome

[Bra!nFreeZe^]

Im getting one this thursday so Ill check it out

[XanderF]

Awesome, let us know what you find!

I have some ramsinks on order and another radiator for my WC setup. I figure I'll probably be taking the whole thing apart for 'upgrades' again this weekend, and a workable vMod on the graphics card would be awesome!

(I had to pull the work I did to date - didn't seem to offer any additional speed on the little resistence I dropped, and no way to read the voltage, so I didn't want to push it)

That auto-slowdown thing is really pissing me off, though. No way to know what the real, running, clock is!

Is there any program that, while running complicated 3d tests, could display the current core clock in some corner of the screen or something?

nVidia's Coolbits overclock control SEEMS to know when it is 'too far' on memory. But, it's allowing core clocks that, in use, it decides it needs to reduce. That's kinda annoying, I want to know what my card's limits REALLY are!

(Right now I'm running 485/780 on it. 800 was possible on the mem before removing the stock HSF to put on a waterblock, I imagine it will be again when I add some ramsinks and a card cooler blowing at it. Still, sometimes the core clock seems to drop.)

[Bra!nFreeZe^]

Dont you think that forcing older dets to work on the card would fix the auto-slowdown thingie ?

[XanderF]

Perhaps, but the reason I sold my 9800 for this card was that I prefer nVidia's drivers a lot.

Especially since I've tried the 56.56, I've been hooked. I LOVE that application profile application through auto-detection. I'm sure ATI will copy this - at least, I hope, lest my next upgrade be a very one-sided decision.

I think I used the 45.23 before with good effect. That, at least, had FSAA that worked in 'Raven Shield' - the 56.56 breaks that. The official 53.03s (current WHQL) just break WAY too many games for me to use.

What drivers would you recommend? I could certainly try them!

(As an aside, I have no way of knowing....for sure....that this is what is happening. It just seems during very intense 3d scenes that my video card just stops for a while - say, 30 seconds or so - and when it starts up again the framerate is much lower. From what I understand, that's a symptom of the card auto-downclocking. During cool periods of the day, it doesn't seem to happen - and, if I run it at 475 instead of 485, it seems okay as well.)

[OperativeSix]

Originally posted by XanderF

(As an aside, I have no way of knowing....for sure....that this is what is happening. It just seems during very intense 3d scenes that my video card just stops for a while - say, 30 seconds or so - and when it starts up again the framerate is much lower. From what I understand, that's a symptom of the card auto-downclocking. During cool periods of the day, it doesn't seem to happen - and, if I run it at 475 instead of 485, it seems okay as well.)

Textbook description of the 5900 cards throttling back the core speeds. I'm curious as to how it determines the scale-back speed, though. I know it doesn't default back to 300mhz (like in 2D mode), as when I clock the core at 500mhz with poor cooling, it will throttle to ~370mhz. Seeing as it clocks from 400mhz to 300mhz default, it could very well just be 75% of the default speed. Perhaps this could be another way around the throttle, by just setting the clock speed 33% above what you want it to be?

[Bra!nFreeZe^]

Originally posted by OperativeSix
Textbook description of the 5900 cards throttling back the core speeds. I'm curious as to how it determines the scale-back speed, though. I know it doesn't default back to 300mhz (like in 2D mode), as when I clock the core at 500mhz with poor cooling, it will throttle to ~370mhz. Seeing as it clocks from 400mhz to 300mhz default, it could very well just be 75% of the default speed. Perhaps this could be another way around the throttle, by just setting the clock speed 33% above what you want it to be?

Hmmm that might be it ! until now my card havent throttled back yet and im running my 5900XT at 480mhz and 781mhz

[TodB]

Weird..... I checked all the capacitors on my GB FX5900XT and the close ones showed around 2.5V..... I got 2 side by side capacitors, both measuring 2.53V.... ain't that quite low for a Vmem?!?

The Vcore showed 1.43V...

[Bra!nFreeZe^]

Can you take some pics as where to measure the voltages ?

[TodB]

Well... no problems.... I'm sure about the Vcore, but the Vdimm is on hold.... I'm going to snap it now, so we can discuss about....

[Bra!nFreeZe^]

Allright Im looking forward to seeing it

[TodB]

OK, here's the GPU Voltage reading point.... will check the DDR reading point tomorrow

[Bra!nFreeZe^]

Thx d00d! btw have you vmodded it yet ?

[TodB]

Well... yeah..... the 3D Vgpu jumped from 1.43V to 1.59V and the GPU freq jumped from 480MHz to 535MHz... that with the present cooling, of course

[Bra!nFreeZe^]

Nice I need details right now! mine does 500mhz stock gpu cooling...and I have a Volcano 12 right here that just needs to be mounted

[TodB]

Well the second ISL6522 chip on my card seems to control the Vddq voltage.... I'm not 100% sure, but I think there's no way that 2.8ns memory will run 800MHz/2.5V....

I'm left with one last chip on the back of the card, will test it later..... if I find an info about....

[XanderF]

Excellant, and be sure to post pics of where to mod and what you did!

I think I had made some headware, but it was a false start. I'll be pulling my card out again next week to add ramsinks, and I'd like to vMod it while out.

[Bra!nFreeZe^]

TodB cant you post the vgpu mod so far ?

[macci]

Anyone got problems flashing 5950 bios on these 5900xt cards??
I've got the albatron 5900xt model (runs 3dmark03 at 525/803 with stock cooler 1.59V Vgpu) and flashed the leadtek 5950 bios in there. It boots up fine and reads 5950 in the bootup but WinXP is all phucked. 4bit colors etc at some point it gave some 'no enough resources' error. Anyone seen this? how to fix it??