Can a “Secret” CPU Setting Really Improve Boot-up Time?

The TuneUp Blog team previously proved that several common Windows myths, such as disabling the Dr. Watson program and tweaking Windows’ prefetch folder, are, in fact, wrong. In this blog post, we’ll explore yet another fallacy that has been a hot topic of discussion in the Windows community for a long time—a “secret” CPU setting that can help improve boot-up time.

The myth

According to a variety of sources, Windows Vista and Windows 7 only use a single processor core during the boot-up process. Thus, enabling all of the other cores should boost boot-up performance, right? Apparently, this is simply done by opening up “msconfig” (pictured below) and going to the “Boot” section.

Users will then find a button called “Advanced options” that leads directly to the so-called “secret” setting, which is also known as “Number of processors”. Windows sources claim that this is the place where consumers can enable all of the processor cores of their machines—for example, two on a Core 2 Duo processor and four on a Core 2 Quad processor.

This is supposed to significantly improve boot-up speed. Keep reading to learn why this is wrong!

Myth busting – reason 1

We tried this tweak on three different machines, and didn’t find any improvement in not one of the PCs’ boot-up times. To debunk the theory even more, we limited the number of cores to one. The results from one of our test beds:

As you can see, no matter what settings we used here, the boot speed did not change.

Myth busting – reason 2

Changing the value of the “Number of processors” will only result in an entry called “NUMPRO=x”, whereas x stands for the number of CPUs added to the boot configuration database of Windows XP, Windows Vista, and Windows 7. This will define the maximum amount of processors for Windows to use during the boot-up process. So, in fact, this is a troubleshooting setting; if you have boot-up problems, you can use this setting to limit the number of CPUs, and therefore find out which of your processors or processor cores is defective.

Myth busting – reason 3

This is more of a warning. The TuneUp Blog team has received a lot of reader feedback about experiencing boot-up problems when changing the CPU setting. We have not experienced this first hand, but it seems to have happened to an alarming number of Windows users.

The bottom line

Leave this setting alone. Don’t change the number of processors, as it does not work and might make things worse for your system.