BSOD,and X800xl silent pipe

Right here goes i have upgraded my system withe the X800xl i have done a clean install of xp the same ati drivers as before the card is the agp one.
The power supply is a 550w AMD approved PSU i have a skull case with fans and a antec GPU fan sits above the X800xl card.
I have noticed my machine sometimes gives me the BSOD i have not had one of these for a least a year,i have opened my pc to check the card it is not even hot.
The machine has only BSOD on me 3 times now but it does raise a question to me i read somewhere that someone else was having problems with the gigabyte x800xl with the BSOD.
I have just played and finished(again)Half Life 2 the machine only BSOD once.
I dont think it is when it running Big 3d games because it just done to me again playing that pixel hungry Isketch.
Any ideas?:stop: