Well the problem with VM ware is that you need special drivers for the guest OS. VM designed their "own" HW. F.i. Videocard, so you can only run an OS which has support for it. With VPC you'll always see an S3 Virge, an Intel NIC, 1 CD. SB16. The Windows version doesn't virtualise the CPU, it does a preanalysis of the code and can detect problematic code sections which get rewritten on the fly. So as for pure CPU tasks you get to 90-95% of the original CPU speed. What currenly is slow are things liek FileSearch operations. But they new 4.4 version has speedups of up to 30% in this area so they are putting in the 2nd gear now.