I found this while playing around with Stumble Upon!
When you have a computer with a recent model CPU, chances are it's a dual-core CPU. Both Intel & AMD have been producing dual core CPU's for a few years now. By default, Windows Vista will only use a single core during boot-up. You can easily change this from the System Configuration utility:
- In Vista's Start Search type msconfig & hit the [Enter] key on your keyboard
- Once System Configuration has started, select the Boot tab and click the Advanced Options button
- In the BOOT Advanced Options dialog, check the "Number of processors" check box, and choose 2 (or 4 if you have quad core) for the number of processors.
- Click OK twice.