I hate to disagree, but I have 4 computers at home all PIIIs w/450-600 Mhz and 384 MB RAM. I am running WinXP, Win98, Win2k, and Redhat 9. As far as I can tell the WinXP box outperforms the Win98 box. Although I have to admit any performance tests I have done have been specifically for my work, not for MAME, YMMV.