the kyro beats the freaking $hit out of the mx in 32bit. look at anandtechs review about the kyro, it barely looses any fps when compared to 16bit mode.
anandtech's review is from june, the drivers have been updated soo many times. get the newest drivers, and see it soar. Sure it's not as good as the gts, but has much better 2d, and better image quality.
the Kyro murders the mx, it's not even a question to ask.