There are things you can do to make booting faster, but they would be at the expense of runtime performance. For example
- a time consuming element of the boot process is testing the RAM, so reducing the RAM will speed boot up, but at the cost of overall slower system performance.
- Another major component of boot time is loading the OS and applications from the hard drive, thus my previous suggestion of getting rid of the relatively slow hard drive and replacing it with a Solid State Drive.
- Deleting ~/Library/LaunchAgents and ~/Library/Loginitems.plist will save the time required to launch all the various startup items.
The simplest way of speeding boot time is never shutting your computer down. All of the ones around my place run 24x365 and are rebooted only when required by an upgrade, or once a week (as recommended by Apple).
