Seemingly everywhere I turn on Mac forums, users are reporting that Exposé on 10.4 seems unnecessarily choppy with more than three windows (whereas Panther handled this task fine). This problem has been plaguing me for some time now, and it wasn't until yesterday that I began trying to figure out a solution. After an unsuccessful fix of zeroing of my hard disk and doing a full 10.4 system reinstall, I began poking around the graphics tools that come with XCode 2.0 -- since it obviously wasn't related to some third-party program.
I found a property called Beam Sync in a Developter Tools program called Quartz Debug that, when disabled, made Exposé work just as it did on Panther for some reason unknown to me. I'm not exactly sure just what Beam Sync is, which is why I am not entirely sure of the consequences of disabling this -- use it at your own risk! So if you have been having problems with Exposé being choppy on 10.4 even with your Dual G5 and 9800 graphics card, try the following steps:
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050518113854620