Frame Rate Drops In Windowed Mode

[admiraltennek]

Hello there. When I run the game in fullscreen mode the frame rate consistently stays at 60fps, however when I switch to windowed mode (which is how I prefer to play games in general) the frame rate becomes very unstable and randomly plummets to around 10-20fps for no apparent reason (this also only happens when I'm in certain areas of the game, and not graphically demanding ones either-- ie. in hallways, small rooms, etc). I never had this issue with "The Dark Descent", so I'm a bit confounded as to why I'm experiencing it with this.

My PC specifications are as follows:

Operating System: Windows 7 (64 Bit)
CPU: Intel i7 2600K
GPU: GeForce GTX 670 (latest drivers)
RAM: 16GB
Hard Drive: Crucial M4 128GB SSD

Thank you for any help in resolving this annoying issue.