I performed a test on my Vista laptop, C2D 2GHz, 2GB Ram, NVidia 8400 using VMWare Workstation and Screentoaster.com.
I thought the best way to test the efficientcy of the imp[lementation of Screentoaster.com’s screen recorder, I would boot a VMWare machine. This is a very intensive task, and during the recording I did find my computer a bit sluggish, Vista reverted to basic non-Aero display mode, and expectedly took longer than average to boot the virtual machine. Here is the video output.