Okay, so its not the process priority. I have a fishy feeling about one or more of the drivers on XP-64.

ïÏøçö: I installed the audio driver. Was there a reason you didn't want to install the audio driver?

What I'll probably end up doing is wiping the hard drive and re-installing Vue after XP-64, but before any drivers, so that I can measure the render speed before the drivers can take effect.

I think I'll wait to hear from e-onsoftware before doing a clean install.

Thanks everyone for your help.

Charles