Ok, further update on the TI4600 and some more observations:
First off, anyone with a GF3 or GF4 card should really go download the 29.42 detonator drivers. These have made a world of difference in terms of stability and a bit of a frame rate increase I had the 29.32 drivers prior to this and experienced lock ups and other stability problems). Interestingly, these drivers have not been officially released by nvidia, but they leaked out somehow.....I downloaded my version from a Russian website (good thing I can read Russian!)....LOL!
You can find them here:
http://www.3dnews.ru/download/drivers/nvidia/The download is on the right side of the page.
I have done a lot more tweaking on the card settings and the monitor refresh rate. I now run my monitor at 100Hz locked. I have downloaded and use a tool called "NVMax4" which gives access to some settings on the GF cards that you don't normally get via the display properties.
You can download it here:
http://www.geforce3-gamer.de/geforce3-gamer/news.phpIt's a german site, but the download is obvious.
I have not only tweaked settings, but overclocked the TI4600 a bit as well. I now run the core at 310mhz and the memory at 675mhz (defaults for the MSI TI4600 is 300mhz core and 660mhz memory).
Settings are now:
1024x768 32 bit
QUINCUNX AA
trilinear filtering (don't use anisotropic filtering with AA on, things look like crap)
4x AGP
sideband addressing on
fast writes on
Detonator 29.42 drivers
Monitor locked at 100Hz
VSYNC off
Sitting on the runway with no other aircraft in sight I am getting 110-125 fps.
High alt, no aircraft in sight and not much terrain in view (important distinction about the terrain, see below) I am getting 200+ fps.
Unfortunately, when things get heavy, I still drop into the 30's and 40's, but I have found very specific instances when this occurs. It seems after much observation that the terrain is the real drain on frame rates. If I am up pretty high when there isn't much terrain in view, I can still exceed 100fps even with 15-20 aircraft in view during a furball. That same furball at low alt with lots of terrain in view drops the frame rates into the 30's. I dropped my visual range in the game from maximum to one or two steps lower and frame rates are back up again.
At one step below max visual range, 15-20 aircraft in sight at low altitude, I am running in the upper 70's. Two steps below max visual range on terrain and I am pushing 100fps again, even with tons of aircraft, smoke, etc in view.
My conclusion is that CPU horsepower is the real key to keeping frame rates up in AH when lots of terrain is in view. For some reason, the AH terrain is a real beast for the system to handle.
I have tested a few other games I have (OFP, NASCAR 4) and I do not seem to have this frame rate problem with any of their terrains. I can now max out OFP settings and get ridiculous frame rates, same for NASCAR 4. Soooo, the AH terrain is the killer suspect. hopefully my new Dragon Ultra mobo, XP 2100 and a gig of 333mhz DDR memory will fix this!