I run it on a 1.2GHz Athlon, 640MB RAM, Geforce2 Ultra 64MB, Windows 2000.

1024x768x32bpp detail levels maxed. No complaints about speed vs. bots or with 2 other players over the net (all on one local ISP). A little bit of lag in the DM-Asbestos map vs. those 2 other players, mostly just on startup. More lag when I jumped into a 32 player game, but still playable. I could have knocked down the res/detail there. I didn't check actual framerates.

I had no stability problems playing vs. bots by myself. When playing vs. my 2 friends, I had one glitch where I seemed to lose the rest of the players but stayed in the level. After that, I had many problems with not being able to rejoin the game.

I don't like the join game interface. You have to connect to Epic's master server to find a game to join, even if you know the IP address of the guy hosting the server and just want to join a private game over the net. That master server seemed a bit wonky. It constantly lost communication with the server I was trying to join. The favorites feature didn't seem to work. I'd much rather be able to just type in an IP and connect. That way, if the game server is the problem, at least I've narrowed it down. I think Epic has gone this route to force most players to log into their servers to combat piracy. Of course, if anyone know a secret handshake to connect via IP address, do tell.

The other stability problem (related?) was that my system shut down a couple of times mid game (monitor lost signal, lights on my optical mouse went dead, fans still whirring, I don't know what else was still running). I don't know whether to blame the software or overheating, but the problem only showed itself during multi-player.

As for the game itself? Lotta fun. Turn up the physics detail level and watch your opponent's bodies (or parts thereof) flop around and slide down hills and such. Even more dramatic with the low gravity mutator enabled.

Actually I was mistaken. I didn't have everything maxed. World Detail was set to high instead of highest. Decal Stay was set to normal instead of high. Everything else relating to graphics was set to the highest setting or checkmarked. Audio was software 3D. Resolution was 1024x768x32bpp

I checked framerates using instant action vs. the default number of bots.
In the outdoor map (DM-Antalus) framerate fluctuated between the low 20's and the low 30's. It occasionally dipped to 19 in a firefight. Sometimes it stayed in the high 30's.

On the indoor map (DM-Asbestos) framerates were even better (my lag in that net game I described earlier must have been related to the number of players in the game). Low to high 30's. Sometimes in the 40's. Sometimes in the high 20's.

I noticed they have the framerates color coded. 40+ = green, 30-39 = yellow, <30 purple. If there are colors outside that range, I didn't see them.

I'll have to compare my results to some online play sometime.