quad core Mac Boot Camp issues

My manager decided my new machine was going to be a nice fast Mac Pro and I'm limited to XP Pro (rather than Vista) because our tech support isn't supporting Vista yet. My first ugly surprise was that the machine in Windows XP can only see 2 of the installed 4 GBs of RAM and apparently there is nothing to be done about that. (I already knew to forget about virtualization via Parallels or VMware because they don't support firewire).

So when I go to the task manager I see 8 processors. When I'm rendering with Vegas, I would expect to see all 8 processors cranking away. What I do see is full activity on the first processor, and a very small amount of activity on the other 7 processors. The rendering doesn't seem any faster than my old 4 year old PC work station. In fact, with HDV footage it seems a lot slower. Right now I'm rendering from 1080p HDV to NTSC widescreen avi and it's taking about 4 hours for a 13 minute video. Yes, there is a fair amount of green screen and compositing, but it seems like a long time.

I've also been getting a LOT of hanging and crashing with Vegas 8.0b on the new machine.

Is there anything I can do to improve this situation? Thanks for any thoughts anyone might have.

Mary Waitrovich
UW-Madison