Although rather different to this article, I’ve now used VirtualBox on WinXP for ~3 years.
My modest WinXP PC has only a single core AMD64 3200+, and only 1GB RAM. 256MB is used by the ATI Radeon 200 shared graphics.
So, small footprint is probably more important than ultimate performance.
Despite this, 32-bit Windows 7 does work on VirtualBox 3.2 running on my WinXP Home. It runs well enough to allow testing of software applications.
Linux “guests” work even better: Both as installed versions and as LiveCDs.
Not mentioned in the article: VirtualBox provides virtual network configurations both between its “guests” and with the “real” world.
