I'm running vB3 Beta on my private forums on a Dual Xeon 2 Gb RAM box, and it's smooth as silk - my mysql processes are dying properly, I don't get runaway apache processes anymore, my server loads never go above 1.0 - it's much better. Mind you, this may also be because I got rid of all third-party hacks and addons and running default vB for a change.

Just sharing this observation...