Mine got slow and sluggish when I installed button mapper and mapped one button. Once I uninstalled it, it is back to normal. Probably nothing to do with yours but thought I would throw that out there. Overall the KM2 is a solid device. IMHO.
Sometimes, I turn it off (long press on the power button) and back on again.
Anyone know how to do a factory reset on the KM2 box please?
Are you using an external USB drive or a MicroSD configured as internal storage? I ask because I had similar problems with my Strong Leap-S1. They were resolved as soon as I unplugged the USB drive.