Well in single player mode it runs perfectly fine but when ever i boot up multiplayer and i do the test map thing it begins having terribe frame rate. Also once afterr i have swiched alteranate timer to true, and have installed amd dual core optimizer it worked till i have shut off my computer. Then next time i do every thing i did last time and i still get ****ty frame rate.

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OS: Vista Ultima
RAM: 2g
Prossesor: AMD DUAL CORE
GFX: nVedia 8600
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And yes my drivers are up to date

Happens to me too, I have nVidia 8400M GS and Vista...