Excellent (and correct) answer, Jesse.
Alternative answer:
Because the graphics in Breakaway limit themselves to roughly 90% of CPU usage, so that it doesn’t stall your computer. It should never reach 100% no matter how large you make the window.
Benny’s computer might be a few years old, in combination with a high resolution screen.
On my 2GHz Pentium-M Laptop with 1440×1050 screen, Breakaway can use 90% if you maximize the window.
However, on the machine I developed Breakaway on (Core 2 Duo E6430 and nVidia 7600 GT) full screen never used above 15%, and with the main window closed, the audio engine used well under 5%.
///Leif