I have made some tests with the driver releases from nVida.
First my configuration :

CPU P4 3Ghz
512 MB RAM
nVidia Grafic card FX Go5600 64 MB RAM 8 X AGP
A6 Pro Vers. 6.31.4

I started always the same level with no moving and watching the fps.
The first test, I made with the old driver version 44.85. The fps
is about 33 - 35. I installed version 56.64 , 67.02 and 71.50 .

All I can say is, that the old driver is the fastest. With all the new
driver the fps is about 11 - 12 !!! Usually, it is the best, to have the
newest diver on the system. What does this mean ??? Has A6 the possibility
to work with the latest drivers or does this mean we have to stay with our
old stuff, that we do not loose fps ??? Please do not say it is my level or
my system, it is driver depending !! But is the A6 renderer to old to go
with the newest technology ?? We all know that A6 is not the fastest engine.
Try to use shader and you can see where the engine stays, but what's for
the future ????