Um low FPS in games is not a Mobo issue.
What settings are you gaming at? If it's at max at 1920x1080 and max settigns, you're only gonna get 28 FPS with a 5770. http://www.guru3d.com/article/geforce-gtx-460-review/16
You might actually get less since you have a CPU that's very bad for gaming.
Best way to improve would be upgrade to at least a 5850, which will put you at above 40 average FPS.