I have not been using my sim for a while and I came back to it after adding the new Nvidia 56.56 drivers. I run at 1280x960 and with aircraft like the FSD Cheyenne or Seneca I usually get around 20FPS at best on or near the ground and no better than that in the clouds if I have the blow up instruments on. Today I did a few practice approaches and noticed that I had a steady frame rate in the low thirties and my instruments are noticeably smoother. I have made no other changes to my system.P4 2.4 - 1.5GB Ram

Nvidia claims better AA and shadow features in the 55.xx driver series--but it's hard to say for sure whether that is where your improvement is. Depends on what settings you fly with (AI, Autogen, Clouds, etc...). What drivers did you run with prior to the ones you're running now? I'm really interested in your comments because it's the first I've heard of a GeForce 4xxx series card having measurable improvement by going beyond the 3x.xx driver sets. Every time I've upgraded performance has been the same.-John

I did not change a single setting with the driver Change. I still use 4XS for my AA setting and Anisotropic Filtering is application controlled. My sliders are 80%+ on everything. Aircraft and sound settings are maxed out. Other than the driver change I made no changes and I have a substantial increase in FPS. When using aircraft like the FSD Cheyenne and Seneca I am always watching the FPS because they get pretty low at large airports. I just did approaches in to KBOS and my FPS never dropped below 28. I used to get 15FPS on the ground there. As I mentioned before the best I could ever get with these aircraft either on the ground or in flight with the instrument blow up open was 20FPS. Now I sit a rock solid 30+. Something has occurred anyway!

What drivers did you upgrade from?

What ever was the last set from Nvida. 53.03's if that sounds right.

I have to agree with your findings. I have not changed anything either except the new nVidia 5664 drivers. I fly the PMDG737, with frames locked at 20 and in front main view I now get a steady 19-20, which is remarkable since this is the view that has all the instruments working. I have a P4 1.7ghz rig with a G4200ti/64 card. I run with 1280x960 res, and 2xq AA, and AF at 2x.It does seem that the 5664 driver has improved performance.CheersBob