I had a problem where my mouse and keyboard would be choppy. The mouse pointer would work at "1-2 fps" and the keyboard would keep missing letters as i was typing them.
Since both are USB-Devices, i suspected a problem there immediately, so whenever i got this problem, i would suspend the computer and start it again, for the problem to be gone. The problem started appearing when I plugged the mouse and keyboard directly into the computer rather than the USB-Hub in the screen.
I'm using a Logitech UltraX Flat and a Razer Lachesis, on a Dell Latitude E6510.
The way I temporarily solved the problems was to switch the keyboard and mouse back to the screen USB hub and restart the computer, after which the problem was gone. If anyone else should happen to run across a more elegant solution, however, they're welcome to give another answer. This is mostly just here for anyone who runs into the same problem and wants a quick fix.
Same problem in Ubuntu 12.04.1 LTS, mouse jumpy, choppy. Tried rebooting, changing sensitivity and acceleration, no improvement. But when I plugged the mouse into a different USB port, that fixed the problem--it now moves smoothly.