So after reading various articles on the internet, including the ones on this site, about the fact that X800 Pro VIVO cards are essentially XT cards but with 4 pipelines disabled and clock speeds set lower, I saved up and bought an Asus X800 Pro TVD (VIVO) card, in the hope that it would be a simple case of flashing it with an XT BIOS to get a £400 card out of £300. Alas it was not to be... I have successfully flashed the card with the Asus X800 XT BIOS from this website, everything seems perfectly fine, yet my PC freezes up totally when I'm playing a game. First I hear a slight click from my PC (although I can't identify which component it comes from), then the picture freezes but the sound continues, a couple of seconds later the sound stops too, although the picture always stays on screen it is completely frozen and does not resume. My PC requires a hard restart. This happens with all of the various games I've played it with, UT2004, Doom 3, Half-Life 2, Warhammer Dawn of War, although sometimes I can play for 20-30 mins without it happening, sometimes it cuts out before the game has even finished loading. (i have never actually got Half-Life 2 to load as far as the gameplay). At first I thought it was a temperature issue, but with using ATITool to monitor temperature, it was tending to stay at 65-75 C when playing games, and would crash at any temperature (it has played games stably at 75, crashed another time at 75, also crashed as low as 50-something). So maybe its not temperature, although can anyone tell me what temperature these cards should ideally be running at? I flashed it back to the original BIOS, using the backup I made, and it has been running fine ever since. No problems at all (Half-Life 2 looks fantastic! although it even did on my old GF4 Ti4800). I tried overclocking it to XT speeds, but keeping it as a Pro with 12 pipelines, and it was also fine. Then I tried flashing it with a retail-ATI Pro BIOS with 16 pipelines, it was also fine. But when I tried it with that BIOS and overclocked to XT speeds, it had the same problem. So what is the issue here? Is it a bad card? Defective pipelines? Bad flash? Bad BIOS? Overheating? Power issue? Or 'other'? Any help/advice would be appreciated. I'll take any suggestions, and can provide any other info or test results that will help diagnosis.