Well, there are a couple of reasons. The biggest reason for Win98 being game friendly is that it allows your games more direct access to hardware components and the drivers for Win98 are well developed. Win2K, on the other hand, puts up this protective barrier, a middleman of sorts, between your applications and the underlying hardware. All access to the hardware must go through this intermediary layer. Some games do not like having to talk to a middleman. The fact that frame rates are sometimes lower in Win2K could arise again from having this added middleman cost, as well as Win2K just itself being a more resource intensive operating system. Another reason might be that some of the drivers for win2k are not nearly as optimized as their counterparts for Win 98.

Xin Li