I have a amd 900 athl on XP Pro...no problems with Processor...Memory I did have a probelem...I was running a gig of memory and the machine was slower than car driving in snow storm. Then I ran Painter from Metacreation and it tells me I am out of memory...So then I installed my free Painter that came with Drawing pad Wacom...It tells me I am out of memory...then I try another graphics program..I am thinking damn...I have a virus that Norton did not catch...so I reformated my hard drive reinstalled everything...3 days later ..(because of Poser) I trying my programs...and no memory...So I tried changing my memory chips around and one did not work...so I pulled it...and everyone of my program came back to life...and ran faster even though I only have now 512 ram. Moral of story...try memory before do anything crazy like I did.