long time to startup AX client

I set up a vmware virtual environment，and migrate AX 2012 from physical environment.

In my test:
test 1#: open one client very slowly, using 60s; 
test 2#: open two client at the same time and the same machine, only use 8s

check cpu/memory/IO no bottleneck, also ,no block or long query  in DB.

who can give some advice,many thanks.