I too have an Athlon XP1600+ processor and I have just switched to XP. Just because you have a Athlon XP processor does not mean you have to run XP. I think the only difference between the regular athlon and the XP athlon is that the XP has some extra cache built in. As for performance, On my machine(DFI AD72, 512mb of DDR, athlon XP1600+, Nvidia Riva TNT M64, Qauntum Fireball 7200rpm) I think Xp was a step backwards in performance. Win98SE may not have all the bells and whistles but Its a get up and go operating system, compared to the sluggish XP. Thats my opinion and I'm still gonna run 98SE regardless, even if my processor is a XP processor.