You dont even need the core maximiser. If you open taskmanager and change the affinity of the program it will achieve the same result.

This game is limited by ghz. D900 Code Reader Software Update. One operation cant start until the previous operation is complete. So regardless of the number of cores it will essentially only use the power of a single core as that is the limiting factor. If, however you have other apps using some percentage of the cpus first core, spreading the program over several core will show an improvement.

What the core maximizer does is spreads the load of the game to all the cores of your cpu. See Supreme Commander: Forged Alliance wasn't designed for multiple cores.

Fa does use more than one core but you will find the first core is the one that maxes out natively. Some things, such as ai or sound or pathfinding or something are used on other threads but these generally are not using the max cpu time.