Because a picture is worth a thousand words.
This is my laptop, an HP 6730b with a Core 2 Duo 2.53GHz processor and 2GB of RAM, running 5 VMs with different flavors of BSD along with other applications. The VMs are running OpenBSD 4.6 (two of them, one with XDM), NetBSD 5.0.1, FreeBSD 7.2 and DragonflyBSD 2.4.1 and some of the other applications are AIMP2, TweetDeck, MS Outlook and Console2 with a PowerShell tab.
The System Information window from Sysinternals Process Explorer is showing the amount of RAM consumed, still 300MB free :-D
Like I said BSD… don’t you love it?