Johnny Billquist wrote:

>
> But I know that people probably disagree with me, so I have just one 
> question: how do I limit the file cache to take no more than, say, 16 MB?
> No matter how much the system thinks it *might* be able to use.


I found the following useful:

sysctl -d | grep vm

I'm not sure if this will improve any performance, but you could try 
setting the follwing in your /etc/sysctl.conf file:

vm.filemin=5
vm.filemax=10
vm.anonmin=5
vm.anonmax=100
vm.execmin=5
vm.execmax=100
vm.bufcache=5