I don't have GeForce, but I think that new direct-x versions are must.
There is soon coming direct-x 8 as final (at least beta is already, and I am using it with V770 TNT2)
So games will also require DX7 at least...
I've never had problems with newer DX7, just with the first final version of it.
Try out DX8 beta, Fscott..
Might be better than 7 and surely better than 6.1, if that 'might' works.
At least DX8 has had no problems so far..
(actually I got 10 points more 3d marks

)