Ubuntu performance improvements

If you have 1GB of memory of more, reduce the virtual memory usage....
$ sudo cat /proc/sys/vm/swappiness
60
$ sudo sysctl -w vm.swappiness=10
vm.swappiness = 10

To make the change permanent
sudo gedit /etc/sysctl.conf
Add the above line (vm.swap...) to the end of the file and save

More useful performance stuff can be found at the Ubuntu Forums

Details on how to update your kernel to ensure you have one optimised for your processor can be found here.