It's funny that you use the word efficient with that processor, because, although it has great specs, caches, speeds, it's biggest downfall is that word: efficiency. If you're going for power efficiency in gaming, look no further than Intel's Ivy Bridge. I agree with Taeran about the 3570k.
Will you be overclocking at all? Just that if you are swapping over to Intel will be a bit more expensive.
Most AMD processord have a 125W TDP, so under full load they draw 125W of power. The current gen Intel processors only draw 77W under load, with the i3's drawing 65W. While also offering generally better performance overall.
AMD chips right now are more geared toward Multi-Threaded tasks, while gaming is much more suited toward Single-Threaded performance.
You have a 'K" edition processor and a H77 board. Chip can overclock but the board cant. Need a Z77 board if you want to overclock (and aftermarket cooling).
So if you want to overclock, get this Z77 board. http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...
If you dont, change the CPU to an i5-3470.