I can play Quake 3 with 45 -100 fps. in 1024* 768.
But in nexuiz at medium settings and 1024 i get 9-45 fps with 25avg maby, EVEN if i put all min/off and 640*480 i get exactly the same fps.

I can't get fullscreen to work maby thats why?
please help!

amd 800 768mb geforceti4400

try nexuiz-sdl.exe instead of nexuiz.exe.
This fixes the no-fullscreen bug for me.

AAAH THANK YOU! The fps only gained a bit but thats always something
But now i got fullscreen! AAAH THANKS!!!!!!!!!!!!!! AT LAST )))
btw what those sdl stand for? what is it?

Well the 4400 is not really a very powerful graphic card. Nexuiz needs more power then quake3 as the engine is far more powerful (rivals with doom3 features wise) and the content is not that much polished and optimized as its in quake3.
You can try to open the ingame console with shift-escape or ` and enter exec low.cfg;vid_restart and see if this helps.. This will really lower all effects and stuff..