I am undecided about which card to buy. I have a XFX GeForce GTS 250 Core Edition Video Card - 1024MB DDR3, PCI Express 2.0, (2) DVI, SLI Ready, FREE Call of Duty 4 Gamehttp://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=5286097&SRCCODE=WEBLET03SHIP&cm_mmc=Email-_-WebletMain-_-WEBLET03SHIP-_-03ship and a XFX HD-577A-ZHFC Radeon HD 5770 1GB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card http://www.newegg.com/Product/Product.aspx?Item=N82E16814150457, can I get some assistance on decideing which is the better by. What I the determining factor when buying a video card for the overall throughput.