Over Christmas I had the chance to relive all the Christmas presents I received from long ago.
Anyway, I wanted to play some MW4 Mercenaries. When I loaded it up however, it seemed that there were a few glaring issues. One was that mouse aim was attrocious, and the mechs in the mechlab were spinning around too fast.
One fix is to use RivaTunerStatisticsServer from Guru3d.com and limit the frame rate to 60fps.
As most computers would be able to play MW4 at high speeds 100+ FPS, it confuses the game engine and the mouse acceleration / look is terrible.