It seems like it is because the game is running on something that makes it able to run as if it was on the OS it was made for. The game is ten years old and wasn't meant for stuff like Windows 7. I get a boost, as well. It's unreal how much just installing it has improved my experience with the game. Seriously. The thing seems to smooth the graphics a bit, which makes any game run better from my experience. With Skyrim, I found that a mod that fixed the meshes up a bit actually made the game run better. I'm only not using most of the overhauls because I use tons of mods that add other stuff to the game.