My mouse movement periodically becomes choppy/jumpy after maybe an hour of use. The problem goes away temporarily with a reboot, but it returns before long. This seems to happen regardless of RAM usage (I'm always at about 3.25/4.0GB used).
The choppiness is exactly what you'd expect from a Bluetooth mouse that's almost out of battery, but this happens both on my trackpad and on my wired USB mouse. The mouse also works correctly on another laptop.
The computer is just a 2014 Macbook Air, but I don't think it's purely a problem of processing power because I didn't notice this problem until a few weeks ago (possibly after an OS update).
Best Answer
Cursor became so jumpy on El Capitan, machine unusable despite all manner of resets ... but cured for good, still cured in Sierra, by third internet reinstall from Recovery partition!
The third time I ran with no hope, but what the hell it's easy enough, and ....no more trackpad or mouse cursor craziness!
If you really want to do it right, back up or make a clone, & erase disk with Disk Utility in Recovery Mode for a complete, clean install.