The noatime option tells an ext filesystem to not update the "last accessed" timestamp every time a file is opened. This enables you to save disk i/o and have you disk caches perform much better.
You need to edit the fstab file to use the noatime option.
sudo vim /etc/fstab
Your fstab file will look different to this. At this point I should warn you that if you mistype this, delete something you shouldn't or otherwise break this file, you Linux system MAY NOT BOOT. You can see below where I have added noatime which is visible in bold.
/dev/hda1 / ext3 defaults,errors=remount-ro,
noatime,auto 0 1
Reboot and if all is well then you should have a faster filesystem.
Ext noatime fstab