svajoklis-1 has a repository of them on github, all the way up to PCEM v17. I think many of them run afoul of copyright. Not sure how he gets away with hosting them on github. Not sure if I'm allowed to link them here either. But they aren't hard to google if you just try "pcem roms github"
Win95/DOS 7.1 - P233 MMX (@2.5 x 100 FSB), Diamond Viper V330 AGP, SB16 CT2800
Win98 - K6-2+ 500, GF2 MX, SB AWE 64 CT4500, SBLive CT4780
Win98 - Pentium III 1000, GF2 GTS, SBLive CT4760
WinXP - Athlon 64 3200+, GF 7800 GS, Audigy 2 ZS