The next thing id suggest doing is going to OPTIONS,PREFERENCES,VIDEO TAB and lowering your DYNAMIC RAM PREVIEW to 1 and your MAXIMUM NUMBER OF RENDERING THREADS TO 1.
Finally if you are still getting low memory errors, Id suggest trying a batch render if its a long edit i.e 3 minute montage full of effects....
BATCH RENDERING TUTORIAL
THESE STEPS HELPED ME ......
be sure to check out my vids on my youtube.... You must login or register to view this content.
---------- Post added at 10:13 AM ---------- Previous post was at 10:11 AM ----------
i made this very quick but it basically just solves some low memory issues and also makes sony vegas run a lot faster.... i hope this helps you as i remember always having issues with vegas