[theandrewbailey]

That's generally par for the course. There's a lot of CPU simulation that happens in RTS engines, like visibility/range testing and simulating hundreds of moving/(semi)autonomous entities, not to mention pathfinding for them. Some RTSes simulate individual projectiles with startling quality. Most of an FPS is GPU work, environments are mostly static (less CPU), and there's some hitbox detection and maybe insane physics thrown in.