Solved by Vasiliy_Kuznetsov in post #2 
              
              
                Hi @eefahd , 
There are a couple of things to keep in mind: 

default qconfigs have different settings for qnnpack and fbgemm.  One setting in particular, reduce_range, if set to False only works correctly in qnnpack and leads to potential overflow in fbgemm.
when weights are packed, the global back…