If you're doing a CBR file (constant bit rate), I'd only change to 2-Pass, and that should solve your problem.. but what source are you coming from? AVI captured from Tape?

If you wanted to do a 3-speed VBR file (Variable Bit Rate), it would make it look a bit better, but you'd have to have a streaming server to make it work properly.

and Mac users won't be able to view it properly.