Caching Expiration in ASP.NET

Question

I want to cache sql view having more than 1 lakh records with more than 600 columns. At present i am caching the entire records in a single cache but it occupies nearly 0.5GB memory of my RAM. But the problem am facing is that i could not maintain the cache in the server for a period where i have set a absolute expiration of 10 hours, But the cache doesn't maintaini in the server for the mentioned expiration time.
I have seen one article which says the size limitation of  a cache must be between 2-3GB.
Please suggest me
* What are the limitations in caching where in a huge data handling project?
*How can i play around with Caches in terms of dependencies both hardware and software?
*What are the measurement criteria that needs to be taken care in Cache sizes and expiration policies?
*On a given day we update the cache atleast thrice. so i need to recache it for certain interval of time. what are the advisables i need to take care of?
 
Thanks in advance :)