More motors cause joystick to get slow

[Batman]

When we try to create more than 5 motor objects (RobotDrive, Jaguar, Victor using C++), our joystick starts responding very slowly so the ArcadeDrive doesn't move the robot until a half second or more after the joystick is moved. This is only our second year, so we could easily be doing things wrong, but we can't find a problem like this mentioned anywhere else. We've tried increasing the Wait time in our main and task loops to 20 and 50 ms but that hasn't helped much. We've seen teams talk about using 10 or more drives, so it seems like we shouldn't be having these problems.

Any help with be greatly appreciated!