It's query and data caching that will speed this up the second and third time round.

I find

DBCC DROPCLEANBUFFERS

will probably get you back to the 70sec mark,

but to get to the original 2 minutes you need to restart the SQL Server.

Very necessary when you are actually trying to work out if your

query optimisations are actually any better or you have just wasted

the last two hours re-writing a script for no result.