2.8GHz Northwood Pentium 4, 800MHz FSB, HT on, Intel 865PERL MB
1.5GB DDR400 (PC3200) Corsair XMS RAM; 2 3 2.5 6 (I think)
120GB 7200 RPM SATA HDD
SB Live 5.1 sound card
Asus Radeon 9600XT, 128MB, AGP
1280x1024x32, 4xAA, no AF
AH sliders full left, animated water off, 512 textures, loaded into RAM (not graphics card RAM)
Ozkansas P1 SW runway Spit V cockpit: 40 fps.
The fps depends entirely on terrain (Karelia is much lower), location, smoke, density of other planes, and view. For example, going into the T34 gunsight view, setting zoom to max, and looking into a forest will drop the fps to low single digits, like 4 - 5 fps. Tank gunsight view is what limits AH for me- flying never causes serious fps problems.
My experience is that AH, like most flight sims, is CPU limited. For example: replacing my 9600XT with an X800XT (which should have had 3 times the performance) had no effect whatsoever on AH frame rates under the conditions listed above. My recommendation is to max out CPU power and go for a mid range GPU- but your mileage may vary.