...which is overkill since your eye can never see more than 30 FPS. So whether it gets 30,60,90 or 590 it doesn't matter. As long as it does not slip below the 30 FPS threshold - that's where your eye begins to pick up jerking or hesitating in the graphics.
I run an AMD Athlon 1.333 GHz with a GeForce 3 and 384 MB of non-DDR memory and have no probs at all. The only games that have even taxed the system a bit are Splinter Cell - my card did not like rendering the light maps on the walls and such, and Flight Sim 2004 - which is because the 3D engine pretty much sucks. I have non-DDR memory because DDR came out shortly after building my rig....ahhh I coulda screamed - but that's life.
My point is you can do a hell of a lot with a little. Run your system lean and mean with minimal background crapola running and you should be fine with any newer card. But beware that any NVidia card with MX in the designation is going to be slower than the non-MX version. MX is the bargain card with lower memory bandwith and slower clock speed, but any NVidia card on a relatively new system will kick major butt.