Weird Framerate Cycling

[xenovitalis]

I'm having a problem where Amnesia's framerate nearly comes to a stop in a regular pattern every 2-3 seconds.

It'll run fine, fine, drop, fine fine, drop, fine fine, drop, etc...

It's a regular pattern. It doesn't matter if I'm at the menu or in-game. I've run Amnesia fine on this PC before. I recently re-installed it for the Justine update.

Anyone else experiencing this?

Platform: Steam/Windows 7
Video Card: GeForce 7900 GTX
Processor: Dual Core Pentium 4 (2.0 GHz)
Memory: 2.0 GB