Undervolting P-7811FX GPU to fix black screen issue

What's a program to change the voltage of the 9800M GTS for each of its profiles? (2D, 3D, 3D extra, etc) Nibitor doesn't seem to work with Vista 64 and I can't find the option in Rivatuner.

A modded bios (or a tool that allows me to make one) that is undervolted is even better. (Like the one andros_forever made for the nvlddmkm issue, except his is for the P7805u)

The reason I'm asking is because of, I'm sure many of you are familiar with, the black screen issue when the GPU is under heavy load. Although it's a sign that the GPU is dying, turning down the voltage (only way I found so far is to disable Powermizer, dropping it from 1.11V to 0.90V) does help.

Thanks for the help.

 

Actually enabling PM alows the GPU to run the lower clocks at 0.90v. If you are having eventual black screen issues when playing try a good disassembly and cleaning of the CPU and GPU cooling systems and re application of all TIM.

The reason to do the cpu as well is if its heat isn't disapated it remain in the ase to heat up the GPU passively. Also if you still have an issue try declocking the GPU to lower than stock settings. Remeber the P78xx, even the P79xx and P68xx, is old now and the TIM is alot less effective and these systems are serious dust collectors.............................

 

I'm positive the issue is not related to heat and/or CPU clocks as I've tried both of your suggestions. So is there a program to declock the GPU that also allows managing voltages?

 

Right, you can't change the voltage. It has been shown while the modded bios will report undervolted it actually still runs at stock voltage. The idea is to lower the clocks and lower stress on the GPU an components.

Now if it black screens immediately at any 3D then there are other issues. If over time you get the black screen lock up then there are other issues. If you overclock the GPU you could have over stressed the chips and no longer can puch them hard (essentially have worn them out).

Now TIM over time will dry out and become less effective. With a good chip if 50% of the TIM is bad the chip may still report it is with in temp ranges but because of hot spots errors out. This can even be true of a new TIM install if too thin as it boils out and creates the same hot spots.

You can research the forum and find many a user who have recovered there system with a good cleaning and TIM application. This ends my input here, up to you to decide if the advice is warrented or not............

 

Well I suppose I'll try it again... no harm in doing it right.

Btw... what did you use to declock the GPU? As far as I'm aware by "declock" you mean declock the 3D extra profile right? Rivatuner doesn't recognize the 9800M 3D extra profile.

 

I haven't declocked as mine runs fine but nvidia tools will let you set whatever clock speeds. Do not use a thin TIM unless you plan to redo it every 6-12 months. The thin tim dries out and or boils out. Thermal pads will hold out better but generally are less efficient overall.

 

Ok thanks, will check it out.

 

Hmm, looks like you're right. (So far) haven't experienced a single crash after underclocking from 600/799/1500 to 530/630/1300. Will do more tests to make sure.