CHECKPOINT Writes all dirty pages for the current database to disk. Dirty pages are data pages that have been entered into the buffer cache and modified, but not yet written to disk. Checkpoints save time during a later recovery by creating a point at which all dirty pages are guaranteed to have been written to disk.

CheckPoint will help us to produce the cold buffer cache.
   
--Execute the checkpoint command
CHECKPOINT
--Execute DBCC
DBCC DROPCLEANBUFFERS
--Execute below query to check the buffer descriptors
use SQLMonitor
select sysObj.name,*
from sys.dm_os_buffer_descriptors bufferDescriptors
INNER JOIN sys.allocation_units AllocUnits ON bufferDescriptors.allocation_unit_id = AllocUnits.allocation_unit_id
INNER JOIN sys.partitions Partitions ON AllocUnits.container_id = Partitions.hobt_id
INNER JOIN sys.objects sysObj ON Partitions.object_id = sysObj.object_id
WHERE bufferDescriptors.database_id = DB_ID()
AND sysObj.is_ms_shipped = 0