Oh well, there's no harm in asking I guess
About the vsync and opengl problem. It seems to be related to ATI drivers so it shouldn't concern Nvidia cards. What happens is that UT doesn't run at constant speed offline and this causes all sorts of weird stuff on a server.
The workaround is to turn vsync on and set FrameRateLimit to 200 or something lower. This last setting seems to make a lot of difference. Also it's a good idea to change the netspeed so it can reach the framerate the vsync is set to. TNSe's page says that netspeed 5500 corresponds with 75Hz @ 1024x768 resolution.
I'm not sure what the problem is but maybe ATI has changed something which causes the game to work too fast (on this machine UT seems to be able to run at 300 in-game fps or more). That's why the frameratelimit would help.
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