8800GT, Decrease Memory Voltage

[nfm]

Hi,
I tried searching this but found nothing much, I know somebody did it here before but I don't remember exact instructions. My card recently at stock volts and clocks would start to artifact my screen while gaming, cause blank freezes and crash nv4_disp.dll driver, no BSODs whatsoever. It started artifacting in Windows also, the Start button in the taskbar smudges. This is nothing new to me and the cause of all of this the stability of memory in the graphics card. I have to lower them to 936Mhz to make Crysis stable. Early 8800GT came with sucky Qimonda chips which were actually being overvolted to 2v . I'm looking for a mod to decrease the voltage to gain stability and get back stock clocks. I doubt XFX would accept my card, even though I registered for lifetime, 'mod friendly' warranty. I still continue to run GPU at 881Mhz and 1.47v and it's been stable for 6 months now.
Thanks.

[nfm]

Looks like ViperJohn got the solution http://www.ocforums.com/showthread.php?t=533418&page=5. Solder Pin 4 to the "B+ out of the on-card Vmem PS". I don't know what "B+ out of the on-card Vmem PS" is

[nfm]

Special thanks to ViperJohn

[dinos22]

i thought largon did the work

[nfm]

I got this image from him, but if it was largon then kudos for him, kudos for you dinos22, and kudos for me for being first to rip off the resistors

[dinos22]

everyone gather for a pat on the back

[nfm]

I soldered 88K resistor, that brought vMEM from 2.01v to 1.98, and man what a difference it made. I'm been testing memory at 1026Mhz and it has been stable for 40min in Crysis so far . I need to get a 50K VR ASAP or dig out a 50K, 27K resistor.

[dinos22]

that's great dude

[jason4207]

Yep, 1.96 worked best on my card.

I got that same pic from Viper a while back.

Thanks Viper!

[nfm]

Well I just ran Crysis again and it crashed in 1 minute I'm trying now 2x 88K resistors in parallel, 1.96 volts. Maybe my memory chips are just dying.

[largon]

There are soldering points for the reverse mod that are easier to solder on.


->
http://www.techpowerup.com/articles/.../vidcard/149/4

[drizzt5]

Hi, I have an xfx 8800 gt with the crappy qumida ram modules. Sometimes at stock it does start to artifact and I'm pretty sure it's because of the ram modules. I also want to volt mod but I wanted to get this out of the way first. I have an accelero and a 120mm fan on it so the cooling should be fine, I usually idle at 38-40C's anyway at 700/1000. I dropped it back down to stock though because every once in a while I'd get the damned little squigglies.

Is there any way to determine for sure that I need to decrease my memory voltage? And if so, then I need help, i've never modded a gpu other then putting the accelero and fan on it, and that doesn't count.

[drizzt5]

I also wanna see what xfx will say when I tell them that I get artifacts with this card because of the ram moudles. Perhaps I'll get an RMA.

[nfm]

I'm RMAing mine, it got so bad. I hope it will pass the initial *solder* inspection. It would crash in anything in few seconds at stock volts. 1.875v worked best, 1.8v card was also very comfortable. @drizzt5, look at largon's pic, it's DEAD EASY to solder on those points. I'm pretty sure -0.05v would solve your problems if your chips are not dying.
@largon, thanks for the knowledge

[drizzt5]

Im going to attempt an RMA if i can get a black pcb'd 8800 gt out of it. Also it will add value to my card and will save me one less mod to worry about.

XFX warrantey covers after market coolers right? And don't they even cover vmods or something?

Btw, you really got 882 mhz on that 8800 gt with a vmod?? damn. you think I could get like maybe 850 with the cooling I have? And what kind of in game performance and in benchmark performance increase did you get from those clocks.

[nfm]

Yeah I could bench at 900Mhz and 918Mhz. The first time I got the card the memory was stable at 1100Mhz for a week, then everything went downhill. The performance increase were just huge, from Crysis (Very High, 1280x1024, DirectX 9 on XP) unplayable state to playable (by playable I mean decent fps, +-40 frames).

[drizzt5]

Ah, well I might be going 4850 if they don't accept my rma and stuff. possibly even 4870.

[drizzt5]

bump, sorry I just found out that I don't have crappy memory, LOL. Good thing I didn't RMA right away.

I'm losing my memory, but i thought i reformated before installing the newest drivers, but apparently not because I just uninstalled the other drivers and then reinstalled the new ones and guess what? No mods running at 740/1020 for a long time so far and just pushing up slowly. Once I hit my max I'll try some mods I guess

Me = failsauce

[Bojamijams]

I'm about to delve into this territory, and am wondering, whats the best Memory voltage for these Qimonda chips for the highest overclock?

I have an evga 8800GT SC and an XFX Alpha Dog (both are reference right and both use Qimonda right?)