Question : Cache Hit Ratio  Sysperfinfo

How do I correctly derive the Cache Hit Ratio seen
on PerfMon from the master.dbo.Sysperfinfo table?
Using  buffer cache hit ratio/ buffer cache hit ratio base
* 100 does not seem to work.

Answer : Cache Hit Ratio  Sysperfinfo

The cache hit ratio under cache manager is the actual number of cache hits compared to each disk lookup.  If it says 60, for example, the cache is hit 60 times for every 1 disk lookup.  A higher number in this area is a good thing.

Buffer Manager "Buffer Cache Hit Ratio" gives you the percentage of hits coming from cache.  With the proper amount of memory in your server, you should get at least 99%.

Hope this helps.