your rig should be able to cope with running Vegas just fine, I would say your settings are probably incorrect.

Your initial setup for the project is just as important as your rendering settings. I don't use Vegas, I use premiere so I can't instruct you directly but your basic settings should be something like this;

Aspect ratio: 1280 x 720

1.0 square pixels

30fps


This is assuming you have HD skate.reel clips downloaded from the EA site... you should be converting the .flv's into another format, I prefer mp4 as thats what I render in.

When you render you should have the same settings as your inital setup only you have to choose a format to render into. I like h.264 mp4's And also your ideal bitrate is around 8mbps.

This seems to work pretty well for me but there maybe someone with better Vegas knowledge that can be more specific, hope this can help you a bit at least