Not a Mac user, so I don't keep up with all of the issues that are specific to OS X, but if you can, try updating OS X itself. You're probably using outdated graphics drivers. Dunno if that's the source of the problem, but it's worth examining.
If Apple doesn't let you upgrade (if they claim your hardware is too old) consider running Boot Camp to boot into Windows (if you have a copy that is) or Linux. Either one tends to deal with less issues (though OS X has improved a lot from what I understand).
If Apple doesn't let you upgrade (if they claim your hardware is too old) consider running Boot Camp to boot into Windows (if you have a copy that is) or Linux. Either one tends to deal with less issues (though OS X has improved a lot from what I understand).