This works for me so others may find it useful.
Control - alt - delete brings up the task manager. I always have it open when editing I can see if the processor is maxing out.
If you find your edtiting is glitchy try setting the priority for vegas in the processes tab to ' above normal. This will reduce glitches and make preview smoother. It may also make other apps more glitchy.
When rendering and doing other things set to ' below normal ' so rendering does not glitch other apps. You may also switch rendering to it's own cores to achieve the same effect.