We're talking 50->60 or more, you might as well go for it. Though i guess wait till June for Haswell? At least that's what i'm doing, i have a Core 2 Quad Q8400. Could only OC by 4%. But then my performance is as good as an A8-3570K, and you can see where that lies on the charts...http://www.tomshardware.com/reviews/cpu-performance-comparison,3370-16.html
Then of course:
This is single player:
I think it is worth the upgrade, because you get a overall platform upgrade too, faster performance everywhere, and games of course.
Though i'd still suggest waiting for Haswell. Probably be the last DDR3 desktop platform, the fastest DDR3 desktop platform (+10% over Ivy) and the most power efficient. Better QuickSync, more x86 extensions, etc.