PC: i5 3570K(@ 4GHz), GTX680(1124/1502)
Setup: 1920x1080, lowest(v-sync on) for max FPS
http://i.imgur.com/l3Hhe0C.jpg
http://i.imgur.com/AVZAZzx.jpg
Result: Ave FPS = 65, Max FPS = 75, Min FPS = 56
Use FRAPS(http://www.fraps.com) benchmark(F11) to check Ave/Max/Min FPS during C3 MP.
I recorded the C3 MP with MSI Afterburner(don't run it with FRAPS at same time) @ 85% quality, 80 fps, 1/2 frame to second hard drive then ran the FRAPS benchmark on the recorded video, but you can just run the FRAPS benchmark(F11) during MP. make sure to run the bench on large map with 16 ppl.
c2 ign = BAD aw3s0m0 / c3 ign = B4NK41