SELECT xyz INTO #Temp from SSMS is 5x longer in one environment than another
For me it sounds like issue with tempdb.. What you could do- check how many files you have on each server- you can see recommendations here. 

Are they big enough and not growing when you doing inserts? What about log file of tempdb?
if they are growing- best would be to expand them before (and keep that way).

One more thing you can check- if they are growing, you can probably make it faster by using instant file initialization.