I'm convinced there is some sort of performance problem with Parallels -- my hunch is that it has something to do with virtual memory swapping, though it might also be something to do with disk access. I've been seeing this with builds 1940 thru 1970. The basic issue is that when I open 2 or more VMs, my mac starts working really slowly. For example, if I switch from one VM to the finder, I get a beachball. Switch back to Safari, get another beachball. Back to finder -- beachball. This behavior is consistent with my mac being low on memory. However, this mac has 2 gigs of RAM, and I can verify (using Activity Monitor) that Parallels is not using over 600MB. Note that for both VMs, I have the Cache policy set to "Favor OSX". Other clues : Launch one VM, and boot windows XP. Play a song in iTunes. Go back to parallels and choose "New Window". Watch the second copy of Parallels launch. On my system, it takes 15-20 "dock bounces" to open! Also, the iTunes auido playback will stutter. Choose "New Window" to open a 3rd VM, and the same thing happens -- it takes nearly 30 seconds to open a new, untitled VM window. I think there is some problem with managing multiple active VMs -- anyone else agree?