Cheap gaming system

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1

I want to build a gaming sytem that will run nearly every game above 40 fps while using at least medium graphics for below 600 dollars (preferably $550). I also plan on playing Civ V and messing around in Visual Studio. I'd like some reccomendations for a PSU and want it to be crossfire compatible Also, How big of a performance dip will I get if I replace the i3 processor with a pentium G860?

Here's the build. http://pcpartpicker.com/p/lEZD

Case: http://www.newegg.com/Product/Product.aspx?Item=N82E16811553003

CPU: http://www.newegg.com/Product/Product.aspx?Item=N82E16819116775

Motherboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157304

HDD: http://www.newegg.com/Product/Product.aspx?Item=N82E16822148840

GPU: http://www.newegg.com/Product/Product.aspx?Item=N82E16814131445

Memory: http://www.newegg.com/Product/Product.aspx?Item=N82E16820145262

2

ten bucks over budget but it has higher quality and faster parts

http://www.anandtech.com/bench/Product/549?vs=538

its probably faster than 2 6770's in crossfire

that asrock board you listed only had 1 full 16x slot, the other was 4x which would gimp your crossfireX