Assuming we're talking a 1080p monitor, or less, that should get the job done. Some of the settings may need to be cranked down in more demanding games.
I'd switch to a newer, higher reviewed mobo, like this: Gigabyte GA-970A-UD3P
If you can spare a little money, the R9 280 isn't much more, and performs a little better in new games.
Finally, the PSU isn't one of the best. Check out the XFX series, 550W should get you by, 650W may be safer for overhead.