Is there any concensus on the best Preview RAM and Render Thread settings for use with ProTitler-heavy projects? Or Vegas Pro 8a projects in general?

I have a hyperthreaded dual-Xeon 2.8GHz system with 1GB of RAM, and I have it set for the default settings of 256MB of RAM for Preview Rendering and 4 Render threads.

I'm happy with the normal rendering speed of my projects, but not the ProTitler parts.

I have this project that is a ProTitler 5 minute long scroll over a jumpback that takes over 2 hours to render to AVI.

Thanks. (And yeah, I'll build a new Quad-Core mid-year probably.)