Well that's pretty quick mate
I noticed the other day that from pressing on to logging into Windows, my sister's PC does it quicker with XP, and she has a Sempron 1.6GHz CPU and 256MB PC133 SDRAM - both less and slower than mine! But then once she gets into windows it takes forever to load all the startup stuff
Edit: Regarding shutdown speed, I have noticed that mine is much faster when my CPU is cooler. Another thing that affects shutdown speed is if you have a second hard drive, having it set to only run when it's being used and shut off after a certain period of inactivity. If the drive is not already running then Windows has to start the drive up again to shut the PC down, which adds a few seconds on.