I am going to install Ubuntu to dual boot with Windows 8 soon, but one of my friends warned me that partitioning my hard drive will slow my computer down. I run on a 500GB HDD and 8GB of ram if that helps at all. Is that true if I do it?


There are several factors to take into account but generally speaking, Ubuntu normally is at disadvantage when installing. This is because Windows is normally at the beginning of the disk, and Ubuntu (or any other distro) is at the end. Disks are faster then closer they are to the start, hence Windows will have shortest seek times, that will give it a boost opposed to Ubuntu.

Another thing is that Windows will not run at the same time that Ubuntu, nor the reverse. Hence while you are running Windows, only your system inherent performance is taken into account. I have not seen (nor imagine) any circumstance that Windows will slow down because you installed Ubuntu.

Bottom line, Windows normally will have the advantage on the hardware, but Ubuntu (Linux) will use it more efficiently. That's all.

  • Thank you for the answer, it was the most explanatory and detailed of all of the other ones. Sep 9 '13 at 16:37
  • Disks (or in this case partitions) are not faster when they are closer to the start. It's the opposite. Here is an useful related post: superuser.com/questions/159890/… Sep 10 '13 at 10:51
  • @YuppieNetworking did you really read the link? To put it simply, the first 125GB are faster than the later 250GB and the speed is less and less the further you go. I don't know what are you referring with "start", but my "start" is the start of the disk which is normally the outer edge of the disk.
    – Braiam
    Sep 10 '13 at 12:21
  • @Braiam - I would like to know weather reinstalling ubuntu and giving it the primary partion which is 1TB help me with speed issues, because right now I am having 100Gb ubuntu parition dual booted with Win 7 (500 Gb partition). Reinstalling would affect system performance?
    – Chinmaya B
    Jun 26 '15 at 17:48
  • @Creator ask another question, and primary partition isn't what you think it is. en.wikipedia.org/wiki/Disk_partitioning#Primary_partition
    – Braiam
    Jun 26 '15 at 17:53

Partitioning will decrease the current size of your Windows partition. This will affect storage capacity, not speed.


It would not slow down your machine because you're not firing it up all together :)

The fact that only one operating system will run in a dual-boot setup, hardware resources like CPU and memory is not shared on both Operating Systems (Windows and Linux) therefore making the operating system currently running use the maximum hardware specification. Regarding the disk issue, well unless the windows partition run out of free space which eventually can be fixed by removing some files.


It will slow down your computer in one case: if you have too small amount of free space on your Windows partition. Thus Windows will show drive C: (or D:) with red bar and will prompt you for cleaning. Just remember that you need to keep ~10 GiBs free space on your Windows hard drive and ~40 GiBs for Ubuntu.


While all ten other answers are correct that there will be no noticeable difference in running time. Boot time will plummet on modern PCs as you will not be able to enable bios caching (at least none of my systems will bios cache to grub) and grub will have a pause and select time of it's own which will slow down boot time (configurable).

Bottom line do it but be aware that you can no-longer boot to windows in under 5 seconds (assumes ssd and bios caching)

  • 1
    Eh? He is trying to see if there will be any difference in the runtime, not the boot time. Some people don't even shutdown their PC and the GRUB delay is something they can change whenever they want.
    – Braiam
    Sep 9 '13 at 22:42

I would just like to add to this that I have noticed a significant performance decrease in my Windows 7 after repartitioning my Windows drive to create space for Ubuntu, although I did screw around with the partitioning quite a bit (created partition to install Ubuntu to, had some issues, repartitioned, more issues) before actually installing Ubuntu to unpartitioned space.

So I checked on Windows whether the drive might be fragmented because this is the only logical reason that I could think my Windows is running slower after the dual boot installation and only came up with a 1% fragmentation. Still not 100% sure why Windows is running slower now though. I might just re-install Windows to see if that helps (note if anyone else tries this, remember to reset your grub).

Could be that I'm just so used to working on a lightning fast linux machine that Windows feels slow now :P


Nobody here has addressed the issue of the windows page file. If you rely on the page file currently and reducing the space available to windows decreases your page file size, it can lower the total memory consumption (hardware + paged) available to Windows.

Really a minor issue though.

  • Err... and how the installation of Ubuntu affects the pagefile? IMHO, Windows >6 (Vista, 7, 8) have the pagefile.sys size dynamically, and is independent of the disk space left but depends on the total physical memory available using the Memory×2 formula for the page file, and it grows whenever it needs.
    – Braiam
    Sep 9 '13 at 22:40
  • @Braiam but how can it grow past the partition size? It cannot Sep 10 '13 at 3:04

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