I haven't tested 3d graphics yet, but up to now I'm sure windows 7 driver is better for multimedia uses.
And one point that I forgot to tell you before:
With the original driver for the device, Windows Experience Index Rating showed 2.3 for aero performance,
and now that I didn't install it it shows 2.0
but reality is something quite diffrent.
(3D graphics are same on 3.0)