Clear entire procedure and databuffer cache
Checkpoint --> Write dirty pages to disk
DBCC FreeProcCache --> Clear entire proc cache
DBCC DropCleanBuffers --> Clear entire data cache

Clear only a particular db procedure cache using undocumented DBCC command
Declare @DBID int
Select @DBID =db_id(‘YourDBname’)
DBCC FLUSHPROCINDB(@DBID) – Undocumented dbcc command to clear only a db proc cache