Okay, I found the problem. The Game Engine was set to software rendering, so I copy/pasted the first option in the troubleshooting section into its place, and the stuttering is gone now. No idea how that happened, but thanks; can't wait to give this a try. Heard a lot of good things about it.

So, I just downloaded and installed TNM, since I had heard good things about it, fired it up... and as soon as the menu is open, the frame rate dies. The mouse stutters around, and menu options take forever to react when I actually manage to position the mouse properly. I tried setting the affinity ...