Yeah, but I don't know how good or bad that video card is. Anyway, here's proof that it should be enough power - at least "on paper":
With one 7870 under full load in their system, their PSU pulled 274W from the wall outlet. Their CPU was idling, so I have to add 95W for an FX-4100 under full load (this would be the absolute maximum). So, if the FX-4100 and the 7870 are both under full load at the same time, then the PSU would be pulling 369W from the wall outlet. Now, the test PSU in the review linked above has about 85% efficiency, so if the PSU is 85% efficient while pulling 369W from the wall outlet, then the system is only pulling about 315W at the most from the PSU.