Concurrent Booting: make full use of your dual-core, multithreaded or hyperthreaded processors in Ubuntu
This is a great way to make full use of your multi-core processors during boot time. I have an Intel core 2 duo processor and I have seen a notable change in boot time. Here’s the how-to: More here
This will reorder the start processes and now CONCURRENCY=shell option can be used. For more information about the dbus, hal and gdm race condition, see this page. Please write in the comments if you have any questions.