I had the exact same problem as many people here. The game was running very slowly even though I have a pretty good PC.

I tried disabling HID devices and that did indeed fix the problem a bit but the cutscenes were still choppy and gameplay was still slow.

Anyway, I saw a tip on another site that mentioned Kaspersky. So I paused protection in my Kaspersky Internet Security and now my game runs perfectly smoothly at 1680x1050 with all settings on High!!!

So for me this is PROBLEM SOLVED!!! :D