I was reading about ways to enhance speed in Windows 7, and I read that you can enable Windows to boot off of four cores vs one to boot faster.

Is there a reason why you do not want to use all four cores to boot?

4 Answers 4


Windows 7 uses what's available on the box ... out of the box. You should not twiddle around with the boot process except when you know what you are doing, otherwise things will become slower / more unstable, etc.

And you should not believe what you read on the Internet.

That said: To tell Windows 7 to NOT use of all the cores that are available is mostly for debugging purposes or some kind of developer tests when you want to simulate a system with only one core. Another reason is to work around buggy installers. Turning the cores off otherwise is not of any other use, the limiting factor of the boot process is mostly disk I/O anyway nowadays (so, buy a SSD when you want a blazingly fast boot .. or don't run that many processes upon startup -> less disk I/O as well).

Again: Windows 7 uses all available cores at boot time. The snippet you read on the Internet is most likely the super-über-hack to go into MSConfig and then check the Number of processors box and then click the number of cores you want Windows 7 to use. People writing about 'how to speed up the boot process' did not understand the what that checkbox is used for:

Number of processors. Limits the number of processors used on a multiprocessor system. If the check box is selected, the system boots using only the number of processors in the drop-down list.

It LIMITS (as in 'puts an upper limit of used cores') the boot process to take only UP TO processors and (this is also important) later on provide only that amount of processors for the OS. If you select one there you will run a system with only one processor.

  • 22
    +1 for this sagely advice: And you should not believe what you read in the internets. May 31, 2012 at 9:37
  • 1
    @Pureferret - Would that not include his own statements :-)
    – Ramhound
    May 31, 2012 at 11:56
  • 1
    @Pureferret: yes. that's where the part i left out in that statement begins: Use your head, think and check what was thrown at you.
    – akira
    May 31, 2012 at 12:48
  • Makes sense, doing some research on this was a good idea :D Apr 30, 2017 at 9:02

This setting is exactly as it's labeled. It is the adjustable limit of number of cores that will be UTILIZED when handling program executions within the Boot phase of a computer.

Despite the MASSIVE bragging regarding Multi-core and multi-threading abilities and applications, Multi-threaded capabilities are controlled by the developer who can or cannot write Multi-threaded operations.

For multi-threaded designed programs that require a boot phase operation, setting the available boot cores to the value of 1 will eliminate Multi-threaded abilities. Setting the available cores to the maximum will reduce boot times significantly !!IF!!! the developer wrote Multi-threaded code.

Not everyone can write multi-threaded code, hence the default boot core is set to 1. Enabling all cores or a few will not have negative effects on the computer. Whoever stated that there will be negative effects has no idea how to write Multi-threaded code.


Windows 10 default install only boots to 1 core. Msconfig advanced set to boot 2 cores.

note: windows always uses 2 cores only after windows has finished booting. I think you are confusing windows boot, and windows normal usage. Windows 10 always enabled the second core after boot finished. This adjustment only has effect on the boot. note: I have a core 2 duo 3 Ghz. SSD. I can see it is way faster booting now with 2 cores.

  • Question was specifically about Windows 7
    – Ramhound
    May 28, 2017 at 17:40

Yes, you should enable all 4 cores.

I noticed this not long ago, I had an Intel i3 quad core processor, and it was running really slow. I then noticed Windows was only using 1 core. If you go to Task Manager (Ctrl+Shift+Escape), and on the Performance tab, it should show on CPU Usage History 4 little graph boxes. That is showing that the 4 cores are being used.

If they aren't being used, then go to Start, type in the search bar msconfig and hit Enter. Click on the Boot tab, then click Advanced Settings at the bottom of the screen. Tick the box that says Number of Processors, select the amount of cores that you have, click OK, then restart your PC.

In Task Manager, it should show all your cores. If it says Parked next to a couple of cores, then go to Start, type regedit and hit Enter. Select Edit->Find, and type in this: 0cc5b647-c1df-4637-891a-dec35c318583. Press Enter to start the search, and once it has found it, on the right side, it should say ValueMin and ValueMax. Double click and change both numbers to 100, then press F3 to search for the next one and change for each. You should then restart your PC, and in Task Manager, it should show all cores working and none of them should be parked.

This sped mine right up, and it's 4x faster now

EDITOR NOTE: This involves editing the registry, which can screw up your Windows installation if you're not careful. These options are also available by going to Start, typing Power Options and pressing Enter. Edit the Advanced Power Settings, and choose the Maximum and Minimum processing power, changing it to 100%

  • 2
    I don't know how this answer applies to the question in any way. The question clearly addresses the boot-up process and isn't talking about unused cores in general.
    – Baarn
    Sep 8, 2012 at 17:51
  • well yes it does the question was Is there a reason why you do not want to use all 4 cores to boot ? and my response was no you should use all cores because its like 4x faster if your using quad core by default windows only uses 1 and my response clearly addresses the boot-up process because when it boots up you want all cores enabled otherwise theres no point in having a quad core if your only using 1 core and he said would booting of 4 cores be faster than 1 core and yes much faster
    – Paul
    Sep 8, 2012 at 17:57
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    -1. As the other answer explains, that option in msconfig is for limiting the number of cores Windows uses. By default it uses all of them, so your instructions will accomplish absolutely nothing, except possibly causing problems down the road if the OP upgrades his CPU and has forgotten about having set this option.
    – Indrek
    Sep 8, 2012 at 19:47
  • well on my computer by default it only used 1 core and i had to enable all 4 and it made it much much faster. it worked fine on me
    – Paul
    Sep 8, 2012 at 19:54
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    By the time you get to the desktop and fire up Task Manager, it's entirely possible that there isn't anything left to utilise all 4 cores. Unless you're saying that your computer was using one core even during a multi-thread workload (like wPrime with maximum number of threads)? If so, then that's definitely not normal and a problem with your computer, and you may well have been fixing the symptom, rather than the cause. As said before, normally Windows should utilise all cores available to it.
    – Indrek
    Sep 9, 2012 at 12:50

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