sp_helpcache can report the amount of overhead required to manage a named data cache of a given size. When you create a named data cache, all the space you request with sp_cacheconfig is made available for cache space. The memory needed for cache management is taken from the default data cache.
To see the overhead required for a cache, give the proposed size. You can use P for pages, K for kilobytes, M for megabytes, or G for gigabytes. The following example checks the overhead for 20,000 pages:
sp_helpcache "20000P"
2.08Mb of overhead memory will be needed to manage a cache of size 20000P
You are not wasting any cache space by configuring user caches. About 5 percent of memory is required for the structures that store and track pages in memory, whether you use a single large data cache or several smaller caches.
