I think the Science Channel or Discovery actually did this a few years back!

They took video of him from one of his races and matched it to video of a running cheetah. Scaled the video so that their heights matched perfectly, started them on the same spot and at the same time and -- yeah, the cheetah out-sprinted him handily.

I'm sure it's on Youtube somewhere but I'm on a low-bandwidth connection right now soooo ... the link won't be coming from me.