Try loading the default (not default camera, just 2007 default) code and using the built-in one joystick drive to control the camera servos.
That's a good way to test if it's a hardware problem or a problem with your cam code.
If it's still slow, try two different servos and two different PWM outputs.
Basically what I'm saying is try to isolate and test every possible cause of the problem until you can for sure identify what the cause is, then re-post, and we'll go from there
