Ok so after my 8800gt burnt out after about 2 years or so of use I just put it a 250gts. I've experience the same problem with both cards where when I play games the system will completely shut off, sometimes within the first few seconds. Its not from overheating. The only way I have found to counter it is to underclock the video card by a lot. Now I can still play games fine with it underclocked but would nice to not have to.
This leads me to think its the PSU not putting out enough or its a POS.
The video card only has 1 power connector, and it needs a minimum PSU of 450w with a minimum 12v current rating of 24amps.
Now heres where I'm not sure about, each 12v rail is rated at 18amps, but I don't use that when fiquring if its enough, I use the 48 available amps right which means it should be enough?
Nice job troubleshooting too. That under-underclocking test is pointing at a power problem.
The GTS 250 is getting up to 75watts (6.25Amps) through the PCI-e slot and up to another 75watts through the PCI-e 6pin power adapter which should be plenty. Either the power supply is having a problem or the PCI-e slot might be having a problem delivering getting the power to the card.
What motherboard are you using? We can check and see if there is any history of this type of PCI-e slot problem.
If not your PSU is the prime suspect.
lol well sure enough its the PSU thanks again for posting, kind of funny this dell 375 will power it and the hec 650 with all the cords and stuff it has won't... maybe it was just a bad psu but will be the last time I will buy that brand. I would have probly just used the dell but the damn main cord is too short, lol its all ghetto rigged.
Can't afford a new PS guess I'll have to settle for underclocked, but at least I finally know what it is.
Yeah I've tried every config I can think of, I just think there is something physically wrong with it, since the day I built it its been the same thing. There are 2-6 plug connector on one rail and one on another rail I've tried all three on the video card eliminating all non essential things on everything else.
Well at least I can play starcraft 2 on high even without framrate lag even when its underclocked thats all I really care about.