Graphics FAO 7900GT users

Guys, as some of you may be aware there have been many 7900GT deaths recently due to overloading/overheating voltage regulators.
The issue stems from the fact that the 7900GT's memory regulation is designed to cope with stock clocks of 1320 mhz. (Although even at these speeds the reg's gets pretty damn hot)
With many cards shipping pre-clocked with a 1500mhz memory clock, the regulators are pushed even further. Add onto this the fact that the memory on these cards can usually hit over 1800mhz and its understandable that the reg's often fail!
For those running stock clocks on 1320mhz, don't feel this doesnt apply to you... Dropped both my GT's down to those memory speeds last night, and the reg's on the XFX card were still nice and toasty.
Not everyones going to have this issue, check the regs on your card whilst its loaded (go careful not to short anywhere...) beware though they get damn hot!
For those people running vmodded GT's this issue is probably going to to heightened... There *shouldn't* be any huge need to run high vMem on these cards, finding the best clocks are coming from UNDER stock volts on the EVGA card, XFX isnt modded yet. Running less voltage does reduce the temp of the regulators considerably by the way

The solution is simple, add some more cooling! Grab yourself some ramsinks or chop up a heatsink and stick em to the regs. Decent quality double sided tape does the job just fine, picked up a roll of today which works wonders.

The regulators in question are shown below (marked in a blue square). They're all the same height which makes things easier. A BGA ramsink is bang on the right size to cover all 3 without too much overlap.


Regs which are the issue



Sinked!!

Note, this DOESN'T affect the 78xx series OR the 7900GTX. It does seem to be affecting ALL 7900 GT's however, irrespective of brand

 

thanks for the information
btw nice vmods

 

Good work - nice-looking sink, too

 

good info - thanks Highland3r

 

Ta for the info dude. I read that 'some chips' get hot, but your diagram has helped no end. I'll get mine sinked up soon.

 

There are some issues with the 7900GTX. Most notably, the "Deep Freeze" test on 3DMark06. For many users including myself, about 48 seconds into the test the screeen tears and graphical errors abound, usually resulting in a reboot.

Luckily, this error doesn't seem to translate into my gaming habits. Many hours into Oblivion have only produced artifacts when slightly overclocked, but not when clocked at stock speeds. This generation of graphics cards doesn't seem to do well with overclocking.

 

Nah, only the GTX's have troubles. The problems on these GT's come from them being awesome clockers and affordable.

Good summary Highland3r, now just to find some decently cheap RAMsinks from somewhere... :\

 

Supurb. Nice one Highland3r, good guide, and I'll keep that all in mind when I get a 7900GT.

 

Drop me your addy mate, have a couple spare ramsinks here will stick some tape on one and send it out for you.

BobCobb, afaik this is a different issue, have you tried playing with PCI-e speeds at all? Jack it up to 110-120mhz and see if that helps.

 

I got that the other night on my 7900GT. Overclocked it to 550core/780(1560)mem. Although, it only managed a few seconds on the Deep Freeze test then all hell broke loose. Artifacts Everywhere, then the screen kept going black intermitantly and desktop was shafted. Had to blindly click start/shutdown. Restarted fine though. That o/c was determined from coolbits/detect fastest settings in the driver settings, then knocked it down a few mhz. All other tests ran fine, proxycon, forest, etc..

 

Cheers matey, PM'd.

 

Also, just found out, disable the PEG-Link in bios. Apparently it automatically overclocks your card somehow. I think that was on one of the rojak threads iirc.

 

highland3r, how did you get the heatsink to stick to the voltage regulators? Did you use thermal paste, or something different?

 

ah this is intresting, so the artifacting issue from the 7900gt's are those little black chips grrr

well whats the deal with the artifacts sticking and not going away, even though the card isnt overclocked.

i dont think id buy a 7900gt again

 

Sometimes when you get artifacts, you can permenantly damage the pipelines/GPU/Shaders, thus the artifacts will always be there. (this only seems to applyto nVidia cards though)

 

oh right, crap ! well at least its on RMA, the thing is i didnt push it at all far oh well ... long live my ATI

 

Hmm.... I've got some old BGA ramsinks lying around (those very ones, actually), need new tape for them though. I've tried normal double-sided stuff and it's worthless for this type of thing, and I think my chance of finding some real frag tape locally is slim to none.

Thanks for the tip though. I've always had strange luck overclocking graphics cards... my 7900gt is working great at stock clocks, but while it played fine overclocked (and tested for artifacts with atitool), it did strange things just booting into windows. Go figure.

 

Firehed, not sure if its the same over there. But for thermal tape - ebay.

 

why not use abit of thermal paste?