Run this to get a breakdown of how much memory is allocated to each memory cache,. The page buffer cache is CACHESTORE_OBJCP and query plan cache is CACHESTORE_SQLCP.

Select [type],SUM([single_pages_kb]) As [single_pages_kb]

,SUM([multi_pages_kb]) As [multi_pages_kb]

from sys.dm_os_memory_cache_counters

Group By [type]

Order By SUM([single_pages_kb])+ SUM([multi_pages_kb]) desc;