I've noticed an odd thing with Android on my Gnex. Sometimes when I do a large upload to my phone, for example a large movie of 1-2GB or a couple of TV series, over USB or AirDroid, the system starts to slow down and become unresponsive. Apps take a while to launch and generally everything is lagging, even if I have more than 6GB of free space. I even had to reset the phone twice because it became unusable. What should I do?

I'm running 4.2.1 takju build.