Okay, finished the game without problems, and I have an overclocked 2500K Sandy Bridge so definitely not tied to CPU speeds, at least not in Intel processors. What I was wondering whether it makes a difference if you install through Galaxy vs. if you use the downloadable installers? Mine was installed through galaxy. Also, Vsync was off, filtering was set to nearest, resolution to 1024*768, fullscreen was on and softwarerender was off. With mine the music didn't work at all during the game but to be honest, I think it added to that nice, creepy atmosphere.
Oh and I'm on Windows 7, did everyone who has this issue have another OS?