When my old PSU blew, a friend installed a spare old 250w PSU in my system, which includes a Sapphire/Radeon X1800 XT. Didn't know any better at the time but after several months of use I think this is why my pc started freezing after a few hours normal usage or 10 mins or so of gaming (removed gpu, usec onboard graphics - no freezing).
1) Is my GPU fried?
In the past i've seen posts / articles about repairing GPUs by ovening them (and I successfully did something similar with an Xbox 360 a while back)
2) Is this the kind of problem a good baking could solve!? Any prospect of repair at all?
I've subsequently replaced the PSU with a more capable one, didn't solve freezing problem
Probably not relevant but system =:
Athlon 64 3400+ 2.4ghz
K8N-VM Socket 754 Mobo
More about :x1800 250w psu freezes fried oven repair
I think your problem deals with the power supply. It could of froze because of low power entering the system.
It works on the onboard because i uses the systems northbridge power instead of its own power meaning the power supply doesnt need to lose much power. You can try using a higher wattage power supply and try it out maybe 550watt should do. I hope it helps
I agree with yab in that there's probably nothing wrong with your graphics card and that it's simply under-powered. Get a quality (Antec, Seasonic, PC Power and Cooling, Corsair) 550 watt power supply installed and you should be fine.