Windows XP/NT only: We've shown you how to trim Windows down to the bare essentials and setting up pre-fetching for faster booting, but how do you know if your painstaking changes are having any real effect? BootTimer, a free measurement utility, asks you to restart your computer, then uses system logs to measure the distance between your boot-up screen to Windows log-in. You'll need to enable the program to run without prompting (un-check the "Ask before running this file" option on double-clicking in XP), and there's a small bit of promotion/donation prompting after it's done, but it's much easier than digging through verbose logs with a calculator. BootTimer is a free download for Windows NT and XP systems only.
BootTimer [via gHacks]