The FX 5950 Ultra definatley notches better benchmarks than the 6200. I think that a flashed 5900 Ultra will also outperform the 6200.
I seriously hope you are not thinking of buying any of these cards; the FX 5900 and 5950 GPUs are no longer manufactured by nVIDIA and the 6200 is Dell or Compaq material. Please don't attempt to play Doom 3 on the 6200.
And AGP has gone the way of Disco, Betamax, and Krispy Kreme Dougnuts
don't use it.
don't buy it.
don't sell it. Techno-newbies are NOT intended to serve as money dispensers.