I updated to RC3 3170 briefly (Mac Pro, 3GB) and it caused serious problems immediately. Even after installing the new version of Parallels tools and rebooting both Parallels and OSX perfromance takes a serious hit. Many operations, especially closing windows on the screen or shutting down Windows XP, cause OSX to hang for a while with the spinning beach ball. I downgraded to 3150 and the problems went away. Looks like 3170 isn't really ready yet... 3150 has been completely stable so far.
Follow-up: The spinning beachball problem is now also happening in the 3150 version that I returned to. Apparently the downgrade performed by Parallels is not complete. This is really annoying, I guess I'm going to have to return to 3170 again.
Hi Drval, It's a new Power Mac 2.66GHz on which I just did a complete clean install of OSX Tiger two days ago, so there's absolutely nothing non-standard on it. In the meantime I completely uninstalled Parallels, did a cold restart of the the Mac Pro and reinstalled 3170 from scratch. Then, before starting Parallels 3170 for the first time, I did another cold restart of the Mac Pro. Then I started Parallels, launched an XP VM and allowed it to install the new version of Parallels Tools. After this I once again shut down Parallels, did another cold reboot of the hardware and started Parallels again. At the moment the spinning beachball problem seems to be gone...