Ubuntu Linux devs have done a great job with the boot time.
There is however a bit more you can do by profiling your boot.
Profiling lets Ubuntu make a list of all the files that are accessed during bootup, it then sorts the files according to how they are stored on your hard disk. So the next time the system is booted, the files would be read faster.
To profile boot you need to follow these steps:
– At the grub menu highlight the kernel you boot most often.
– Press e for edit.
– Choose the line starting with kernel and press e again. Now add the word profile to the end of this line. Hit Enter and then press b to boot
Note that while profiling, the system will boot slower this one time, the next time however you should see an improvement.
Also keep in mind that all this is machine-dependent and also depends on the arrangement of files on your hard disk, so the difference you see might not be huge, or even nil in some cases.