Maybe in true DX9 games where both would perform horribly and it'll be the difference between 5fps and 10fps. In general, no. Anything the fx5900 can run it should run better just because it was an ex-high end. Low end video cards haven't really made much of a head way in terms of performance because that isn't what they are meant for. The majority of low end cards performs similiar and the only difference is features that are added on. I'd assume a 7100 would be more close to say an fx5600.