What does it do?

Game Optimizer uses AppleScript to prompt the user to enter the name of the game. Then using several shell commands via AppleScript, it determines the Process ID (PID). Once i has the PID it then does a renice on it, effectively changing it's priority from -1 to -2. In addition, it renices WindowServer, which is the process that handles the graphics for OS X, to -1.

What is renice?

Let me save you a trip to the terminal. renice allows you to change a processes nice value. The more nice a process is, the less CPU time it gets. The less nice a process is, the more CPU time it gets. You can modify the nice value from 20 (most nice) to -20 (least nice). I have the nice values for the game reset to -2 because it's a nice balance point where it takes enough CPU time to run faster but it also doesn't take too much CPU time from the other processes, which may need it too. The WindowServer is reset to -1 because then it is right under your game in priority for getting CPU time. As a result, the graphics run smoother as more CPU time is alloted to them.