Well I my framerates differ dependent on the map and situation.
Estimated FPS ranges:
In practice mode without players: 40-70 FPS
In wide open maps with full server: 25-40 FPS
City maps with full server: 35-50 FPS
Form time to time the FPS rate drops under 20 FPS. Sometimes it's because of much action, but sometimes it's a certain spot on the map which causes a FPS drop.
But overall the game is well playable for me.
My System:
AMD 2400 XP+
ATI 9800 pro
1 GB RAM PC2100
Audigy2
I play on 1280x1024 4xAA, 2xAF everything on highest exept shadows are blob, Hardware3d sound + EAX
Sound and Video settings have no impact on my FPS rates, though the CPU is the bottleneck.
I have not the newest Radeon drivers installed, though I use this driver version which has the optimal performance for my card. It's not always the best to install the newest driver for your card. Especially on older cards you get better performance with older drivers, because newer drivers are performance optimised for the newest cards only.