Although this problem occurs only when trying to render, I believe it is too technical in nature to post to the Rendering Forum. In all prior versions I could render as many images as desired with no problems. But in 8.1, If I try to do more than 1 rendering per Revit session, the program locks up, and even if I can close the program using the windows task manager, one of my processors continues to chug away at 100% and I have to do a cold reboot. This is on a dual 2.8 GHz Xeon with 2G RAM!

One difference I have noticed between 8.0 and 8.1 is that in 8.0 hitting the "Display Model" button after each rendering clears the page file usage down, but in 8.1 the page file usage continues to grow with each rendering, even with each region raytrace. Is there a setting somewhere in Revit to clear each rendering from memory?

Any suggestions would be appreciated.
Thanks