I need a graphics card that will play wow on low settings for a dell gx620 desktop ( not small form or mini)
First identify your Optiplex from below (provided as example, this is Optiplex 755 family line)
7750 is you best choice, however full height video card is only for Mini Tower (MT), Desktop (DT) and Small Form Factor (SFF) can accommodate only small profile card only such as Sapphire 7750 low profile http://www.newegg.com/Product/Product.aspx?Item=N82E16814202002