I have been testing Sun's (Now Oracle

) VM application called Virtual Box and thought the 'Whats New' on the most recent update was interesting..
http://www.macupdate.com/app/mac/24801/virtualboxIn case someone deletes it, here is the excerpt:
WHAT'S NEW
Version 4.0.6:
VMM: fixed incorrect handling of ballooned pages when restoring a VMM from a saved state
VMM: don't crash on hosts with more than 64 cores / hyperthreads; implemented support for up to 256 host cores (except Windows hosts; bug #8489)
VMM: fixed
guru meditation for PAE guests running on hosts without PAE (bug #8006)
VMM: fixed slow Linux guests with raw mode and recent guest more...