I am running a 3 year old system in the following configuration:
mobo EVGA 780i
RAM Corsair Dominator PC8500
Video 2X GT8800 SLI
CPU Cooler Cooler Master Vertical tower
PSU Ultra XVS 700 watt Modular
Optical Samsung DVD Writer
HD 2X Hitachi 500GB, 1 Seagate 1TB
I have never overclocked any of the components, despite being sorely tempted.
All has run fine until recently. I've started getting complete unannounced shutdowns when playing graphically intense games, in this case BFBC2. I use Rivatuner for the fan controller and it has been keeping my cards within the range of 63-85 (8800gt's always did run alot hotter than the newer cards). The last time this happened I had Rivatuner Monitor going and noticed just prior to the shutdown that the voltage to the cards decreased from 3.17v down to less than 2.5v by the time the unit shutdown. There was also a noticeable decrease in fan noise from the other fans in the case.
I'm assuming my PSU is finally crapping out after 3 years of admittedly near-capacity use, but I wanted to get other's opinions in case someone has run across similar issues and I have missed something.
Looks like a power supply failure. If your looking to get a new power supply from newegg, read the threah I've answered this morning on the subject. I propose a few good units, reviews for it and their price as well. Yeah it took me hours to check one by one every power supply from newegg (it had 24 pages ^^)
The thread is this one. Oh I would have copy paste but it's long so better go see for yourself it's not gonna take any longer and you'll get some professionnal opinions in the reviews I've included with them.
For those with a similar problem, my old PSU was indicating 3.19 to 3.16v under load to the cards as reported by RivaTuner. I purchased and installed a Thermaltake 775watt Toughpower unit and now get a steady 3.21v to the card GPUs. No further issues.