I found this a few minutes ago and I tried to do a forum search to see if anyone else has posted this and I couldn't find anything so here goes:
Adobe has finally released a patch that addressess multiple performance problems and glitches:
The link to both a windows and mac patch are available above.
I have tested the patch and am exstatic to say that the patch addressess all my performance problems! The brush lag is gone completely and all other openGL tasks like rotating the canvas in realtime works as smooth as butter.
Hooray! Photoshop CS4 is finally usable!