Thanks for the news, this may actually affect me. 
I tested 10.6.5 - no spectacular difference from 10.6.4, good or bad. Hopefully it'll fix things for people who had problems.
Manga @ Triumph
"Meanwhile In The Halls Of Titan"...Titan Network Working To Save City Of Heroes
Save Paragon City! Efforts Coordination
I haven't crashed yet since installing 10.6.5.
My guides:Dark Melee/Dark Armor/Soul Mastery, Illusion Control/Kinetics/Primal Forces Mastery, Electric Armor
"Dark Armor is a complete waste as a tanking set."
Seems to run fine for me as well.
Noted that some people on the Apple Discussions forums were seeing games that gave 100-120fps plummet to 7fps after the 10.6.5 update, but not on this game.
http://arstechnica.com/apple/news/20...o-airprint.ars
Graphics drivers fixes, might increase performance as well.