It does but not to any great extent when rendering to avi.

When you render to avi, the audio is done on one thread and the video another. When rendering to mpeg or Windows Media, it is optimized for dual processors.

However, with Vegas you can work in multiple instances of Vegas. So you can start rendering one Vegas project and open up a new Vegas instance and keep editing there. That is a good workflow for dual processors. You use that to do mulitple projects or create a workflow where you finish and render parts of project as you continue editing other parts of the same project.

Also Vegas has network rendering and you can choose make it "network" render on a single workstation. I don't know how it works on in practice, but in theory you can set up many nodes on a dual Xeon workstation and cut your render times down.