the problem comes and goes, sometimes it happens for a game and then won't happen for the next few games. just wanted to see if this could possibly be related to mac client at all since i hadn't had this problem until very recently.
about my mac:
15-inch, Early 2011
Processor: 2 GHz Intel Core i7
Memory: 4 GB 1333 MHz DDR3
Graphics: Intel HD Graphics 3000 384 MB
Software: Mac OSX Lion 10.7.5 (11G63)