EDIT: The FPS Issue has finally been fixed by Nvidia, the current beta 270 drivers have a hotfix inside that will return your AO back to the good old frames you missed. Go to http://www.nvidia.com/Download/Find.aspx?lang=en-us and select your card/operating system/language etc and search for "beta" drivers. Good luck!
Hello, as some of you already know, I have taken it upon myself to test nearly every modern Nvidia card with AO on Win 7 64bit. I will post test results further below if you are interested, take note that I have not tested them with 32bit, but none the less I'm sure if the results are the same, the resolution is too. I have emailed Nvidia and also opened a support ticket in the meantime. I suggest those of you who have this issue do the same so this gets fixed sooner. It is not FC's fault, well other than them STILL running a dinosaur age DX7 engine that is. Nvidia has changed something in newer drivers causing massive FPS loss, I'm sure those of you reading are aware of this.
Currently the only way to get AO to run SOMEWHAT properly on the 400 and 500 series of the Nvidia GTX series is to roll back drivers to an older date back in Nov-Dec. I have posted in most threads these quick fixes, but do realize if you play modern games your FPS will be hindered in those. As I only play AO currently it didn't bother me much, but just be warned. Heck I lost FPS in Minecraft for crying out loud, how sad is that.
For those with oddball series of Nvidia cards or intregated cards, follow these steps.
Firstly, go to Nvidia's driver website [Driver Downloads], then select your OS that is applicable to you, and your video card and your language to match your country.
Secondly and to ALL installing any drivers, when your driver is downloaded be SURE to select the box that says "Perform Clean Install" or else it may hinder your FPS still. My tests showed varied results on this.
Quick links for Windows 7/Vista GTX 400 and 500 users. (Edit: These links are for US/UK/DE/FR users, Other users follow above step guide and select language/video card/OS etc *Thanks Kakadoodoo for pointing this out*)
GTX 400 series drivers for Windows 7/Vista 64 bit that work // [NA] 260.99 Drivers / [UK] 260.99 Drivers / [DE] 260.99 Drivers / [FR] 260.99 Drivers
GTX 500 series drivers for Windows 7/Vista 64 bit that work // [NA] 263.09 Drivers / [UK] 263.09 Drivers / [DE] 263.09 Drivers / [FR] 263.09 Drivers
GTX 400 series drivers for Windows 7/Vista 32 bit that work // [NA] 260.99 Drivers / [UK] 260.99 Drivers / [DE] 260.99 Drivers / [FR] 260.99 Drivers
GTX 500 series drivers for Windows 7/Vista 32 Bit that work // [NA] 263.09 Drivers / [UK] 263.09 Drivers / [DE] 263.09 Drivers / [FR] 263.09 Drivers
On a side note, as I said before, please open support tickets with Nvidia to help speed things up. Just describe your FPS loss issue in AO. If needed you can select your language at the top right hand corner via the flag. Link to support ticket entry [Bug Report Entry]. Update: Nvidia's Q&A lead tech has emailed me and is now aware of this issue and is working on a resolution, however tickets still can help "push" them along.
Testing Results
My System Spec -
OS: Windows 7 Pro 64-Bit
CPU: Intel i7 920 2.66ghz
MEM: A-Data 12gb 1600Mhz Low Timed Memory
HDD: OCZ 120gb SSD Drive
GPU: EVGA GTX 580
SOUND: Creative X-Fi Xtreme Gamer
PSU: Antec 750W
Swapped Cards -
8800GT - All drivers work, 70-100FPS
9800GTX - All drivers work, 70-100FPS
9800GX2 - All drivers work, 75-100FPS
GTX 260 - All drivers work, 65-90FPS
GTX 275 - All drivers work, 75-100FPS
GTX 290 - All drivers work, 80-100FPS
GTX 460 - Only 260.99 and lower perform, 25-55FPS
GTX 470 - Only 260.99 and lower perform, 30-55FPS
GTX 480 - Only 260.99 and lower perform, 30-60FPS
GTX 570 - Only 263.09 and lower perform, 30-60FPS
GTX 580 - Only 263.09 and lower perform, 30-60FPS
Good luck!