My friend claims that dual booting, using two different OSes, requires a multi-core or multi-threaded processor. Is this true?

And if I install additional OSes, will my computer slow down any?

  • 12
    Please read up a bit on what dual booting is. I think you are mixing up dual boot with virtualization
    – Akash
    Sep 3, 2011 at 13:34
  • 17
    And even then Virtualization does not require you to have more than one processor, it can be done with a single core processor but heavy usage in the virtualized system will affect the host and vice versa.
    – Mokubai
    Sep 3, 2011 at 13:41
  • 4
    For the "slow down" part, see: Will my computer slow down if I install multiple operating systems?
    – slhck
    Sep 3, 2011 at 20:07
  • user913233: If one of the posts below answers your question, please mark it as the correct answer using the Checkmark icon just below the vote up/vote down buttons for each post. Sep 6, 2011 at 19:06

5 Answers 5


Your friend does not know what he's talking about.

Dual booting can be done on any computer regardless of CPU.
And dual or triple or quadruple booting will not slow your computer down, it only runs one OS at a time.

Dual booting is when you have multiple OS's installed on the same computer and you choose what OS to boot when you power it up.

The only way dual-booting affects the OS running right now is that the other OS takes some disk space. As long as you have enough disk space for both, you're done.

  • 31
    +1 for the shortest explanation (i.e. the first sentence)
    – phihag
    Sep 3, 2011 at 14:34
  • 7
    -1 for the first sentence. It is uncalled for.
    – Konerak
    Sep 3, 2011 at 19:00
  • 14
    +1 for the first sentence. It's completely true. People should not state things as fact (like requiring dual core for dual boot) if it isn't a fact. I don't even know where someone would have come up with the idea.
    – Kibbee
    Sep 3, 2011 at 19:44
  • 3
    @u913233 If this is the best answer, please indicate so by clicking the checkmark next to the vote buttons. Sep 4, 2011 at 14:01
  • 3
    @Kibbee: notice that my comment was at 19:00, which had first line Your friend is an idiot.. The Community Moderator changed this at 19:41 to Your friend does not know what he's talking about, and your comment at 19:44 probably reacted on that. I do agree that people should not state things as a fact if they are not sure, but that is still no reason for namecalling :)
    – Konerak
    Sep 9, 2011 at 11:53

Your friend is incorrect. Dual booting has nothing to do with anything except the boot commands written to the hard drive.

It doesn't matter how many cores your CPU has, physical or virtual. It doesn't matter how many hard drives you have.

Technically, you can run more than one OS even on the same partition, though this usually only works with OSes of the same type, as in 2 versions of windows.

And if you dual-boot, your computer will not slow down. Installing another OS results in more hard drive space used up, but so long as you have sufficient capacity on your hard drive to fit the other OSes, you won't experience any slowdown related directly to the dual-boot configuration.

However, if you're talking of virtualization, which is where some software "pretends" it's another computer an an OS runs inside that software, yes, a multi-threaded, multi-core cpu is much better, and you'll experience a slowdown.

I recommend you do a little research on the OSes you want to run and why you want to run them, and then decide the best way to go about doing it.

  • 16
    Still, for virtualization, it is not necessary for the computer to have a multi-core processor. You'll just have an extremely bad experience.
    – MBraedley
    Sep 3, 2011 at 13:54
  • 13
    Actually, "extremely bad" sounds overly harsh. I occasionally run Win7 in a VM on a Debian Linux host, with a single-core Athlon64 CPU, and it's quite workable. It isn't fast, but I wouldn't call the experience "extremely bad" either.
    – user
    Sep 3, 2011 at 20:26
  • 2
    Extremely bad is an exaggeration. Sep 3, 2011 at 22:56
  • 1
    Dual booting between two operating systems using a single volume isn't restricted to operating systems of the same family. For example: OS/2 had a dual boot mechanism that simply swapped the VBR of a FAT partition between OS/2's own bootstrap program and another operating system's bootstrap program, whatever that happened to be. It didn't matter what the other operating system was, as long as it was capable of running the utility that swapped the VBR programs back again (or had some other tool of its own for doing so).
    – JdeBP
    Sep 3, 2011 at 23:27
  • +1 for mentioning virtualization, which might have been what his friend was referring to Sep 4, 2011 at 16:44

The number of processor cores/register sets (HT) cores does NOT in any way determine the number of OS'es you can set up in a multi boot configuration.

As long as the OS can run on a single core, it wont make any difference.

  • are there any OSes that doesn't run on a single core?
    – Lie Ryan
    Sep 3, 2011 at 21:21
  • None that I know of
    – Akash
    Sep 3, 2011 at 21:43
  • What operating system did the Thinking Machines CM-5 run?
    – fluffy
    Sep 3, 2011 at 22:20
  • Assuming that the OP is using consumer grade OS'es would be a valid assumption.
    – Akash
    Sep 4, 2011 at 3:57

Central Processing Units (CPUs) which are the processors, or the brains, of your computer. Pretty well everything that is processed in your computer, with the major exception of the video processing, is done inside the CPU. That makes the CPU a very critical part of your system. Generally speaking, the faster your CPU can process the data, the faster your system responds and the less time you spend twiddling your thumbs and watching the hourglass.

There is no relation of dual boot with the dual core. In our institute there are still P4 processor are available and still we use Windows XP and Linux on them.

Users will notice a serious increase in speed when they go to dual-core, even when running applications that are not "multi-threaded". One core will be dedicated to only running the application and the other core will run all the background functions.

You'll see faster response time and generally have a happier computing experience. The only thing is that the processors can increase the performance of software and can boot fast.

  • You use Linux, not Unix. WTH is dual layer?
    – Sathyajith Bhat
    Sep 4, 2011 at 4:33
  • Oh sorry I mistype it and not mind on that thanks for remind me.
    – avirk
    Sep 4, 2011 at 5:03
  • @sathya dual core is also called dual layer.
    – avirk
    Sep 4, 2011 at 5:06
  • 3
    dual core is also called dual layer [citation needed]
    – Sathyajith Bhat
    Sep 4, 2011 at 5:07
  • Oh really sorry I was talking about a DVD which could be dual layer its Dual Core. Don't know how was I so wrong to provide this wrong Info. Really apologies .
    – avirk
    Sep 4, 2011 at 5:12

Your friend is wrong. In my work laptop I have 2 OS, windows and linux and I access any file in the computer from both. It has no impact in performance. Just have to take care that if you mount a partition in one you or your OS has to unmount it before you move to the other OS or it will inaccessible.

  • question about accessing file from the other OS, how, easy as 123??
    – user913233
    Sep 4, 2011 at 1:00
  • @user913233 It varies by partition format, but usually there are no problems and the system handles any oddities for you.
    – ssube
    Sep 4, 2011 at 1:17
  • 1
    @Heineken Not sure what you mean by needing to unmount partitions before you boot another OS, where is that mentioned in the filesystem/OS requirements? Never had to do that.
    – ssube
    Sep 4, 2011 at 1:18
  • An improper shutdown in Windows 7 sometimes causes NTFS partitions to be inaccessible in Ubuntu for me.
    – Akash
    Sep 4, 2011 at 3:54
  • yes, when a system doesnt propper unmount the partition there are flags that prevent it from other mount.
    – Gabriel
    Sep 4, 2011 at 16:45

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