I have tried the beta under Windows XP pro and have noticed the following: 1. Slower rendering 2. program not responding errors, causing a necessary reboot. This did not occur and does not occur when uninstalling the beta version and reinstalling 4.12. The program starts out running fine, then becomes slower and slower.. then simply stops responding. I am back to running ver 4.12 with no problems whatsoever. I run a 3.0 GHZ Pentium 4, with 1 Gig mem, ATI 9600.