After updating to 5.1.1, phone is unresponsive from time to time

Hi Guys,

I recently updated to 5.1.1 and I have nothing but problems. The phone is rooted. From time to time, I would have to do a soft reset (volume down + power) to turn the phone back on.

I have tried resetting the phone and clearing the cache but the problem persists. Any suggestions would be great!

Tuan