Seems to me that caching will help to the extent that you avoid reading from disk. If "20% of the sheets get read 80% of the time" - i.e. some sheets get read many times.

System.Web.Caching has a Cache class. Even though this is in the Web namespace it will work. Here is a quote from a StackOverflow Posting

How are you implementing your cache?

You can use the Cache class from System.Web.Caching, even in non-web applications, and it will purge items on an LRU basis if/when it needs the memory.

In a non-web application you'll need to use HttpRuntime.Cache to access the Cache instance.

Note that the documentation states that the Cache class isn't intended to be used outside of ASP.NET, although it's always worked for me. (I've never relied on it in any mission-critical app though.)

P.S. "LRU" means Least Recently Used. It's an algorithm for deciding what to discard to make room as the cache fills up.

Seems to me that caching will help to the extent that you avoid reading from disk. If "20% of the sheets get read 80% of the time" - i.e. some sheets get read many times.

System.Web.Caching has a Cache class. Even though this is in the Web namespace it will work. Here is a quote from a StackOverflow Posting

How are you implementing your cache?

You can use the Cache class from System.Web.Caching, even in non-web applications, and it will purge items on an LRU basis if/when it needs the memory.

In a non-web application you'll need to use HttpRuntime.Cache to access the Cache instance.

Note that the documentation states that the Cache class isn't intended to be used outside of ASP.NET, although it's always worked for me. (I've never relied on it in any mission-critical app though.)

P.S. "LRU" means Least Recently Used. It's an algorithm for deciding what to discard to make room as the cache fills up.