hi i have a amd a6-3670 quad core processor with built in radeon ddr3 hd6530d graphics card 750w power supply, processor speed is 2.700ghz,oc to 3.000ghz 8gb ram, graphics card memory 4096mb and 1 tb hard disc.i have a budget of 250 -300 for a new graphics card i was looking at the 7970 but would two 7770 ghz edition crossfire be better i welcome all answers thanks