I've just received my new VTX 4850 - not so known brand but i didn't think it would make much difference?
My old graphics card (3870 HD) died recently so it had to be replaced, i didn't look into buying a new PSU to upgrade with my card, as it is fairly decent (Antec Neo HE 550W - had it for 3/4 years)
Anyway, i plugged in the graphics card after removing the old one, booted the pc and it was loading up onto windows, i left the room to go and get some food just as it was on the xp loading screen. I came back upstairs 15 minutes later and noticed that the pc was off, i hit the on button and the pc booted for 0.5 seconds and then cut out, then it failed to do anything again (unless i unplug it then plug the power back in and try to turn it on again)
So i checked the graphics card box and it says 450W power supply and 550 for crossfire, now knowing that my power supply had won awards when i initially bought it, i was sceptical that it could be the problem.
Then i went and check on ati's site to see if the psu was certified for the card, i found 2 completely different answers, firstly :
I've also found somebody with exactly the same problem as me, this leads me to think that the GPU itself isn't damaged! So i'm left thinking it's the PSU, but then again it could be anything - motherboard, ram?
Also i didn't properly uninstall my previous 3870's display drivers, i just deleted the Catalyst Control Centre in add or remove programs, not sure if i needed to go into the device manager or something?
Just read elsewhere that it may be a problem with the 6pin connector on my card, this seems unlikely, but then again my PSU should definitely be coping with this card and my friends is 600W!