Comment 6 for bug 105605

I'm having exactly the same problem in intrepid when trying the incognito livecd (http://anonymityanywhere.com/incognito/) with the following command:
kvm -m 512 -cdrom incognito-i686-2008.1-r1.iso

It is especially noticeable at boot: when the cpu is used at 100%, switch to another worspace; it will fall to 0% and the livecd won't continue to boot till you switch back to its workspace.