About 3-4 months ago I switched out my Nvidia 7600 GT for a Nvidia 8600 GTS. Afterwords my computer started randomly shutting down after 20min - 2hrs in almost any 3D application. (no blue screen, just like if I pulled the plug) I assumed that it was my power supply, which was only 450 watts, so I bought a 650 watt power supply.
This did not fix the problem, (I also rolled back/updated my graphics multiple times prior to getting the new PSU). I ran memtest86+(I think that's the name), anyway it came up with no errors, I also replaced the thermal past on my processor. None of these things fixed it. I checked BIOS temperature, and nothing seemed to be hotter than usual. I've fought this thing for a long time now so any help would be appreciated.
My system specs are
Motherboard: GA-K8N SLI (not sure on this I will have to find the book)
OS: Windows XP Media Center Edition SP2
Processor: AMD athlon 64 4000+ 2.41Ghz (939 socket)
System Ram: 2 gig
GPU: Nvidia GeForce 8600 GTS (by XFX)
PSU: Antec EA650 650W ATX12V Ver.2.2
Just a not when I got the new PSU I connected the 6 pin molex into my GPU, and my computer would post but nothing on screen, not even BIOS. After many hours of frustration I used the adapter that came with my GPU that changes 2 four pin molex into one 6 pin molex, if that helps anyone.
If anymore information is needed just post because I be checking this post constantly for the next few hours, thank you for any help you can provide.
Did you uninstall the video driver and re-install with the new card installed? Install Speedfan and monitor the 12V level. If you have a faulty PCIe power connector you should RMA the PSU, it may have other faults.
There may be many reasons for this to be happening. Memory on your graphics card may be faulty (by factory error) wich could couse your system to shut down every time the memory on GC overheates. But in my opinion the problem is that ur useing PCI-e 2.0 GC on PCI-e 1.0 slot motherboard. One of the points of switching to PCI-e 2.0 was that it can transfer more power over the slot it self. And imo your motherboard can't handle that and every time when u get in demanding 3D rendering situation and your GC starts draining more pover and your PC shuts down. Go to a friend or some1 who has PCI-e 2.0 mobo and try your GC there with your own PS and cabels. Try to use same games, same resolution, and in game details.
I had a similar problem, but it used to happen even if i wasn't doing anything on my PC... It got fixed when I changed my PSU, but since that didn't work for you, try this:
Change the Cable to your PSU
if the problem persists, then
Take your 8600 GTS out and put it back in
and if that doesn't work, then
Unplug everything from your motherboard and put it back together again.
had exactly the same problem on my step dads pc. it turned out that that cooler for the nforce chipset had failed (fan was stuck with gunk) replaced it with a new one no problems since. his problem was that he could surf the internet read emails etc could do it for days on end, however run a game and anywhere between 20 mins and an hour would shut down.
It seems to be a heating issue, I removed the side of my case and put a floor fan right next to it and never had a single problem. I cleaned out the case (it wasn't that bad and put the side back on, so ill see how it goes.