Você pode encontrar o que está armazenado no buffer pool (cache de dados) usando a consulta abaixo:
A partir daqui :
select
count(*)as cached_pages_count,
obj.name as objectname,
ind.name as indexname,
obj.index_id as indexid
from sys.dm_os_buffer_descriptors as bd
inner join
(
select object_id as objectid,
object_name(object_id) as name,
index_id,allocation_unit_id
from sys.allocation_units as au
inner join sys.partitions as p
on au.container_id = p.hobt_id
and (au.type = 1 or au.type = 3)
union all
select object_id as objectid,
object_name(object_id) as name,
index_id,allocation_unit_id
from sys.allocation_units as au
inner join sys.partitions as p
on au.container_id = p.partition_id
and au.type = 2
) as obj
on bd.allocation_unit_id = obj.allocation_unit_id
left outer join sys.indexes ind
on obj.objectid = ind.object_id
and obj.index_id = ind.index_id
where bd.database_id = db_id()
and bd.page_type in ('data_page', 'index_page')
group by obj.name, ind.name, obj.index_id
order by cached_pages_count desc
Excelente referência: dentro do mecanismo de armazenamento: o que há no buffer pool? de Paul Randal.