Stuttering

[nickypants]

Hey! I love the game, but I'm having some performance issues.
I have two 7870s running in crossfire, an i5-3570k overclocked quite a bit, and in spite of this, the game is incredibly jittery. I use RadeonPro to monitor GPU temperatures in addition to other things, and even in fullscreen mode (which usually ensures crossfire is active, if supported), neither of my graphics cards seem to be working very hard - they're both at idle, desktop clocks. I'm not sure if this is responsible, as some games seem to run fine at idle clock speeds, but I'm definitely getting significant stutters in Runner 2. I've tried without RadeonPro even installed, at multiple resolutions, fullscreen/windowed, and with a few different ATI drivers, and nothing seems to fix the issue.

Any advice? Am I doing something horribly wrong?!