performance optimization

Hi Everyone, Ive been reading through a lot of articles on how to tune a linux box.....operating system specific....but just havent been able to stick to a particular piece of information....Apart from the hdparm command.... Ive used it on my linux box FC3 at office but it doesnt do anything great as the chipset ATI RADEON is not supported by linux... $uname -a Linux mymachname 2.6.9-1.667 #1 Tue Nov 2 14:41:25 EST 2004 i686 i686 i386 GNU-Linu I read somewhere that we can lower the swappiness............but that has got me even more more confused ... My question is when does the operating system decide that it should now use the swap space? And what exactly is swappiness?

Does it decide to use the swap once the RAM is full or does it switch over to use the swap in the middle (when the free RAM space is still available) because that is it what I understood by reading the article about swappiness....

I tried out the swappiness command on my office system like this..

#catproc-sys-vm-swappiness

#sysctl -w vm.swappiness=10

Your suggestions please

Thank you Danish