if you mean dual cpu's ..... the answer is murky ..
it certainly runs smoother and better on dual cpu's and does use dual cpu's for some things ... but not rendering (except read on) except mpeg rendering with no effects, pans ,crops etc will use both cpu's ...
you CAN use both cpu's if you use network rendering and run two rendering agents on your system .. this is not always pratical , so you can frame serve out of vegas also to another encoder ....
you can also run 2 vegas's (or more) , one on each cpu ..
Yeah... VEGAS does not utilize the Dual Processors the way many other NLE's do. Would be nice if it did... Renders would be theoritically complete in 1/2 the time.