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Does configuring the number of CPU cores used during boot help anything?


Hi, Leo. I received the following tip and I would appreciate your opinion on
its validity. “Put your CPUs to work while booting. On the majority of
computers, Windows adequately sets how many CPU cores a computer can use.
However, there are cases where Windows uses only one CPU core to process the
entire boot up… etc.”

Now, I’m going to cut the description of this particular tip short because
as we’ll see in a moment it doesn’t really matter.

In this excerpt from
Answercast #20
, I look at a common misconception about a boot setting
configuration in Windows. It’s best to leave it alone.


Boot time settings

The concept that this particular question and tip is getting at is that, for some reason, Windows “appears” to be using less than all of the cores on your computer at boot time.

The reason people think this is because there is a setting that allows you to specify the number of cores to use during boot time.

I’m not going to get into that setting because the whole concept is wrong. It’s actually a myth. With the transcript for this audio, I’ll include a link to an article within that discusses specifically this tweaking myth as far as back as 2008.

The bottom line is that the setting that people are looking at – the setting that this so-called tip is expressing – is in fact a debug setting that allows people to specify the maximum number of cores to be used while booting. If you don’t specify this, which is the default, then all cores are used appropriately.

Even though the user interface for this setting might look like it’s indicating one, in reality that one is grayed out because it’s set to use the default. The default is all cores.

Debugging boot time

The reason this setting even exists is because, as you might expect, multi-threaded code is somewhat complex and the ability to actually debug boot time in software is a little on the difficult side.

So this setting allows the developers to say, no, don’t use all four cores on your machine just use one so that we can get through the boot process and see if that’s what’s causing a boot time problem.

Leave the default

You should never, ever have to look at this setting and should never change it. Leave it set at the default.

If you have boot time speed problems, this is not the solution. If anything, this setting can only make your boots slower.

End of Answercast #20 Back to – Audio Segment

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