Note: Install these packages at your own risk and this may cause an unstable system or it might break your system.
Install the Ubuntu boot packages to increase your boot speed, these packages contain instrumentation to aid in boot performance work, and packages proposed to improve performance. It will install a new kernel and readahead
To install these packages open a Terminal (Applications->Accessories->Terminal and type:
sudo add-apt-repository ppa:ubuntu-boot/ppa
Or add it to your software sources using:
sudo apt-get update
sudo apt-get dist-upgrade
and you’ll be prompted to install the necessary updates to your system.
It will take 2 reboots before you notice any real improvement. This is because the updated packages need to create a “pack file” to read from when booting.
A less drastic solution would be to check what services are being brought up at start up (under system, preferences) or you can compile your kernel (again, at your own risk), to customize it for your computer.