Can you be more specific? Assuming your comparing TurboCNC to Windows controls?
Are you comparing parallel step/direction pulse rates only? Pulse rates can vary greatly from PC to PC. Motherboards and processors can have a big influence on the attainable pulse rate. Mach3, can run at several pulse rates, from 25Khz up to 100Khz. But most PC's can't run at 100Khz, and many can't run faster than 25Khz.