4870 with 512 mb is going to be better than a 4850 with 1gb
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161296
or
http://www.tigerdirect.com/applicat...?EdpNo=5509358&csid=ITD&body=MAIN#detailspecs
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161296
or
http://www.tigerdirect.com/applicat...?EdpNo=5509358&csid=ITD&body=MAIN#detailspecs