When performing SQL Server benchmark testing and performance tuning, it is essential to test against a clear cache.
SQL Server stores common queries in RAM, so after the first run of tests your performance is likely to increase.
To replicate a benchmark test on a clear cache, DBAs can use the following commands;
-- Clear the data cache
DBCC DROPCLEANBUFFERS
-- Clear the stored procedure cache
DBCC FREEPROCCACHE
