I do not know why? But I found that Windows XP computers using only one core at boot time. If you want your windows xp is faster at start-up, you must change it, this is very easy. Here’s how:
Go to start menu program
On the right column click on the run menu. (Or you can press your keyboard keys Windwos + R)
In the next step typed msconfig in the text box, then click OK.
The new window will pop up the System Configuration Utility, select the boot.ini tab, then click advanced options.
Give a check mark on the left NUMPROC and fill in the number of core with two.
A window will appear to change the system, press the “restart” and you’re done.