Tuning Memory

[Darwin Zins]

I was running Mandrake 9.1 and I very rarely used the swapfile.  
Fedora, is swapping my applications out and using the ram for file 
cache.  Is there any way to change this?  To make it so that it never 
swaps applications out unless it absolutely has to?

Right now for example my system has been sitting idle for the last few 
hours, the file cache has grown and grown in memory use, while User has 
gotten smaller and smaller and the swapfile has grown in use.  Right 
now I would say 80% of my ram is in use by cache and 20% by 
User/Shared/Buffers and the swapfile has 70MB in it that must be from 
User.

Any help would be greatly appreciated,

Thanks,

Darwin