In case anyone is interested, I just had to extensively reconfigure my machine to accommodate Autodesk's lovely licensing policies, and in the process I did some quick testing of VMware Fusion, Parallels & Boot Camp. The reason being that the Autodesk activation system is not compatible with Boot Camp so I wanted to decide what VM to install into.
Attached is a little chart of the results. Keep in mind that this is not a properly controlled experiment nor reliable benchmark. I just opened the same fairly complex project in each OS and quickly ran the 3D model and rendering to see if there were any big differences.
Curiously the only significant differences were in the 3D modeling with Vista64 in Boot Camp running slowest and Vista32 in Parallels the fastest (surprising huh?). Unfortunately Parallels managed to trash my Vista32 Boot Camp partition (after the test) so I couldn't run the Boot Camp-Vista32 test. It also made me rebuild my Fusion-Vista64 VM. This is probably because Parallels does not officially support multiple Boot Camp partitions so I had to do some editing of the PVS file. It also showed real problems in OpenGL (may not be a problem with other video cards) so I trashed my Parallels VM in disgust.
Anyway I hope this is useful to some of you as I have just wasted 16 hours that I would have much preferred to spend on billable work.
BTW: DO NOT INSTALL AUTODESK PRODUCTS IN A BOOT CAMP PARTITION. The activation will eventually break and may even lead to Autodesk revoking your license. This may also apply to computers set up to dual boot Linux so be careful.
PS: Anyone who complains about the ArchiCAD hardware key should be reminded of other companies' charming policies. At least with the key, I can run ArchiCAD on any computer I want in OS X, Vista and XP without having to ask permission from Graphisoft every time I want to make a change.