I'm running P6 on a Win2000 and it runs like a dream. I've had the mem bug only once and it was fixed by simply changing the bucket size from 64 to 50. It slowed the render down very little. I still have not updated my drivers for my Radeon 9600 (it's nearly a year old) and I've had no problems with it. I also only have 512MB of RAM on my AMD 64 machine.