Yes it's good enough, you only need a good 500w. It is tier 2 which is respectable. If you have not bought it yet then yeah go for a tier 1 unit especially as you having an overclocking CPU
You spend $600-700 on GPU and CPU alone and want to skimp out with a lower tier unit (even if it is seasonic)? Just get the XFX TS Gold/seasonic gold 650 or evga g2 650 All three will work just fine and don't cost much more.
Yes it's good enough, you only need a good 500w. It is tier 2 which is respectable. If you have not bought it yet then yeah go for a tier 1 unit especially as you having an overclocking CPU