I use VIrtualBox and I've noticed I have to do "nonfs nosshd xvesa" to get PM to boot in VB.
The VM I use has 1GB of memory so I don't think it's memory related.
Note: the boot help screen (F1 then F2) shows "nossh" rather than "nosshd".
I just tried pmagic-4.9.iso-21Jan,213733 under VirtualBox 3.1.2 on a Windows 7 machine and it hangs on NFS, SSH. If you give it "nonfs nosshd" as boot parameters, it boots to black screen. Adding "xvesa" gets it to boot to the desktop and then all works as expected.
I just tried 4.6 & 4.7 and they boot with no extra parameters. 4.8 hangs at NFS, SSHD and needs XVESA like 4.9.

