in all the games that i play a radeon ddr doesnt need its preformace enhaced, so i couldnt realy conceder another card to be a "performance-enhancer". also the gefoce2 have lesser over all visual quality. furthermore, a radeon ddr and standard geforce2 gts have about the same preformace overall. if you do realy feel that you need a faster card, and you feel that incresed preformace is worth the hit in image quality and over $350, throw away your radion and get a geforce2 ultra.
but before you run and blow your cash on a geforce please take the time to see it in preson on a good monitior, maybe there is someplace near you that you can buy it and then return it if it does not meet your needs. get the latest drives and take some time surf the web and or write a few emails so you can look at the 2d. turn v-sync on and see if you can play a game without texture tearing and still have a smooth preforming card. try to alt+tab in and out of a few 3d apps and see what happens. then tell me you like it more than your radeon.