Between Window and Full Screen

Speaking of which, if you remember it runs fine on full screen and only gets problems when alt+entering to window mode. Does window mode just intentionally burn more memory?

The program for windowed mode makes your video card render things in the game as well as on your desktop, making the game choppier. It's not noticeable at all with high-end video cards but your video card is an integrated one that shares its memory and doesn't have its own personal memory for rendering games.