What do you mean require does not require external power?
powered by just the PCI-E port?
Best card for under $200 is 7850http://www.newegg.com/Product/Product.aspx?Item=N82E16814202004
Best card for under $200 using just the power from the PCI-E port is the 7750
take your pick:http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=-1&isNodeId=1&Description=7750&x=0&y=0