Re: Problems with GTX 295
First thing I would try is install driver version 185.20. THis is a great driver even though it is "ALPHA" I am running this on my GTX295 and it fixed a few of my gaming issues. Nvidia MUST GET THEIR ACT TOGETHER and release a great driver for this card, as the official 181.22 driver blows balls. Secondly: What are the amp ratings on your 12v rails on that PSU? A single GTX295 needs 31AMP's (JUST FOR THE CARD ITSELF) plus a needed 10% IN RESERVE. Ideally, you want a PSU with a single 12v rail to maintain the cards needs under load. Most people have PSU's that have 3/4/5 12v rails that are only 15-20a each, and that is NOT RECOMMENDED for this card. You have 2 of these, so you need 62A on a 12v rail to maintain these beasts. See where im going? Even though your PSU was great for your Quad SLi 9800GX2's, they only needed 20a each at most. The 295GTX is a hungry bastard, and really needs a GREAT PSU behind it to maintain stability. If you were to purchase a Silverstone 1000x PSU with 80+amps on a single 12v rail, I'm willing to bet with the 185.20 driver, and this PSU, your issues might be solved.
ASUS P5Q-PRO @ 408FSB / Q6700 @ 3.71GHz AIR COOLED / eVGA GTX295 @ 725c*1585s*2400mem / 4GB G.SKILL PC8500 @ DDR1025 / AUDIGY4 / WD640GB / WD80GB / 28" Hanns-G 3ms LCD