Well - I shall try to give yo a bit of a guide (if I can)
I use eon softwares Vue5 Esprit 3d rendering software. There is a default benchmark to run & it gives you a total time to render scene result at the end. So obviously lower times are better.
Vue is very processor intensive & uses a lot of memory
Computer - default mac mini core duo 1.66 512mb ram.
Software :
Parallels beta 2 (with virtualisation working) (ive only got 512mb ram so the virtual pc is only running on 200mb ram)
Render time 17:03
(note: running vue on win xp with 200mb ram is insane - i'm surprised it even worked.)
BootCamp - windows XP - same macine same software
Render time 8:41
osx 10.4.6 same machine - osx PPC version of vue (same release as windows version)
render time 28:43 (rosetta!!)
As a reference
p4 3ghz
2gb ram
windows xp
render time 15:09
Review: I'm very very impressed with the Native XP (boot camp) performance. and amazed that it even run in a VM with 200mb ram let alone return a half desent render time. PPC version running under rosetta - well that's to be expected.
Hope this helps
Matt :-D