Using P5 with SR3 for 2 weeks now at WinXP Pro and AMD XP2100+. Didn't have any problems until yet. Didn't use many features until yet though. The conversion to Vue4.2 works also quite well. Only slight problems with multiple runtime directories. I think it's a matter of the OS (Win2k should solve the memory issues) and the installed RAM (equal or more than 512MByte). A common graphic adapter (I'm using GeForce Ti4200) and you should only have few problems. The multiple runtime capability, the new render engine, material system and cloth room are very useful extensions. Didn't like the face room and the new hair system though.