core i5 750 going hi wire after 30 minutes of play

After 30 minutes or so, the game suddenly stutters and the fps are dropping, the sound gets stuck for a second and then over again
(iam using an ATI HD 5770 and I have installed the latest driver)
when Iam turning off the game, the cores usage is over 50 percent and the 4th one is always over 90 percent which never happens out of MNC
so, there is still an MNC.exe process running even after I quit the game, and only after I turn that off the processor goes normal again

I have the same processor, except running a 5850. Had the same problem too after the latest update where I started to notice that the FPS just kept dropping with each progressive match I went into. The slowdown always seemed to start from Spunky Cola onwards, and then it just kept getting slower with each map that follows; to the point where the sound would start stuttering. Restarting the game would return it to normal before going into the same cycle again.

It wasn't a temperature problem either because I checked that and the temps were usually around the 50-60 degrees mark during gameplay.

However, upgrading to the latest 11.2 drivers seemed to fix the problem. MNC still shows the odd thing where it would say 'mnc.exe has stopped working' everytime I quit the game.

I tried that, and it keeps happening
its really annoying