I had a similar issue. My computer has USB 2.0 ports but evidently, it is implemented like a hub of sorts and having older devices like a keyboard, mouse, camera, etc was forcing it to USB 1 speeds.
So, I bought a $15 USB 2.0 card and kept all the old slow stuff plugged into the motherboard ports and the iPhones, iPads and a USB hard drive I've since acquired plugged into the new card and holy freaking crap it was like night and day.
It went from dreading a sync to laughing as the bar flew by.