Hi I bought my liquid z630 with android 5.1 half a year ago. Since then I got many system crashes and freezes. Every time I try to clear the ram it gets less and less ram recovered. Eg.: Brand new phone's acer aid kit cleared ram from 95% to 25-30% nowadays it does only from 95% to 45-50%with no apps running. It doesn't depend on reboots, nor factory resets. Haven't really installed any new apps in that time period.