USM Noise 24-70 vs 70-200

My 70-200 II is makes much more noise when focusing than my 24-70 II... Is this normal? In comparison I can barely hear the motor in the 24-70 II while the 70-200 II is definitely noticeable. Any thoughts?

I think, that is the IS you are hearing, and that is normal.

You can't hear the USM motor, what you can hear, is the parts moving, but than you must really listen carefully.

Try turning off the IS, and see if you hear the noise then.