The official Microsoft Windows 8 (64 bit) disk space requirements are the same as Windows 7: 20 GB.

In actual practice, how does Win8's disk space usage compare to Win7's? Specifically, how does disk space usage compare after a clean install of each? I'm thinking the new Metro stuff must take additional space, but MS could have slimmed down the rest of Windows at the same time.

  • Exactly, the added features make it weight a bit more. Oct 22, 2012 at 0:30
  • You mean how many GBs is needed on HDD? Or which uses HDD better??
    – Searush
    Oct 24, 2012 at 21:02
  • @SEARAS: How many GB's (after fresh installs, for a fair comparison)
    – Leftium
    Oct 24, 2012 at 22:24

7 Answers 7


The Test

To try and make a fair comparison, I went for Windows 7 Ultimate SP1 versus Windows 8 Enterprise. Both editions were 64-bit. These are the most full-featured editions of the respective operating systems available, so could be considered as a "worst-case scenario". SP-1 was already slipstreamed into the Windows 7 Ultimate ISO, as supplied by Microsoft via TechNet.

The test consisted of two identically specified Virtual Machines running on Hyper-V - 1024MB of RAM was specified, and no network adapter was connected (to avoid auto-activation or any automatic updates). The systems were each installed onto newly created VHDs, the default options were chosen, and the first user account was created by setup (named Fred, both times if you're interested). As soon as it reached the desktop, the system was immediately shut down.

The Results

The VHD's were mounted as read-only into my main OS, and the properties for each were brought up.

Windows 7 Ultimate SP1:

Windows 7 Ultimate SP1

Windows 8 Enterprise:

Windows 8 Enterprise

The Conclusion

Windows 8 Enterprise takes 3.38% more space than Windows 7 Ultimate SP-1.

Other Interesting Points To Note

On a blank hard disk, Windows 7 will create a System Reserved partition of 100MB, whereas Windows 8 will make it 350MB:

enter image description here

WinDirStat from the host computer onto the mounted VHD's gives the following output (drive F is Windows 7, H is Windows 8):

enter image description here

WinDirStat run on the Windows 7 VM gives:

enter image description here

WinDirStat run on the Windows 8 VM gives:

enter image description here

  • Nice answer! Can you check results in WinDirStat, like I did? I'm curious if WinDirStat gets different results depending on the version of Windows... just the total sizes of the drives is enough.
    – Leftium
    Oct 27, 2012 at 12:14
  • 1
    Sure can, bear with me :) Oct 27, 2012 at 12:17
  • Leftium, what does WinDirStat do about hardlinks? If it just counts them multiple times then you basically get a Windows directory that's inflated to twice the size.
    – Joey
    Oct 27, 2012 at 12:20
  • @Leftium Answer updated to include WinDirStat. Oct 27, 2012 at 12:25
  • @Joey: I think WinDirStat counts hardlinks multiple times. That will inflate the stats..
    – Leftium
    Oct 27, 2012 at 12:28

I took the plunge and installed Windows 8. Before installing Windows 8, I installed Windows 7 for a controlled comparison. Quick answer: both Windows 7 and 8 consume similar disk space, a little over 17 GB.

The exact answer depends on how Windows 7 and 8 compute file/disk sizes. Windows 8 simultaneously consumes less space and leaves less free space than Windows 7. In addition, Windows 8 reports a total disk size that is nearly a gigabyte smaller (on the exact same hardware) Percentage-wise, all the numbers are almost exactly the same:

           GB used       GB free       GB total  
Windows 8  17.3 (27.9%)  44.8 (72.1%)  62.1 (100%)   
Windows 7  17.6 (27.9%)  45.4 (72.1%)  63.0 (100%)


  • Both installations were done on the exact same hardware, preceded by a clean format of the entire drive
  • Windows 8 version: Windows 8 Pro 64-bit
  • Windows 7 version: Windows 7 Ultimate with SP 1 64-bit
  • Interestingly, Windows 7's required system reserved partition is 100 MB while Windows 8's is 350 MB
  • Used/free space numbers taken from WinDirStat

Windows 8 results: enter image description here

Windows 7 results: enter image description here

  • It's interesting your figures have come out considerably higher than mine... Oct 27, 2012 at 12:16
  • @GrahamWager: Hmm.. I wonder why my results are about 2X the size of other answers? Perhaps there is a difference on virtual machines??
    – Leftium
    Oct 27, 2012 at 12:19
  • 1
    @GrahamWager: Ahh~ maybe 64 vs 32 bit explains the different results.
    – Leftium
    Oct 27, 2012 at 12:24
  • good point, should mention both mine were x64 editions, I'll update my answer Oct 27, 2012 at 12:25
  • 2
    Well, I guess the 1 GB vs 4 GB of RAM accounts for about 5 GB of the difference (pagefile.sys and hiber.sys)
    – Leftium
    Oct 27, 2012 at 12:36

After instaling Windows 8 Enterprise on VMBox - 11 GB (explorer)

I remember that after installing windows 7 it was much less space, around 7 GB!


In my experience Windows 8 is comparable in size to Windows 7.

After doing an upgrade of Windows 7 Ultimate, Windows.old was 21GB. After installing some Windows Updates on Windows 8 Pro, C:\Windows is 19GB.

Two months later of regular everyday usage, it has grown to 22.5GB. I think the main culprit is WinSXS.

That 22.5GB doesn't include Metro style apps (C:\Program Files\WindowsApps).

  • 1
    This is pretty false as you're comparing an used system to a fairly new system. Oct 22, 2012 at 0:29
  • @TomWijsman Yes, you were right, I've updated my answer. Oct 22, 2012 at 4:41

I have installed Windows 8 Enterprise edition on a virtual machine. Within Windows 8, Explorer displays disk usage as 10 GB but the virtual hard disk is in reality 8.22 GB.

  • 3
    I don't know what's real anymore...
    – Alix Axel
    Oct 27, 2012 at 1:40
  • 1
    Since Vista, Windows has the concept of hard links which means a file can exists once but appear in multiple locations (using those hard links). This is maybe the reason why Explorer is confused and gives a higher disk usage.
    – ZippyV
    Oct 27, 2012 at 12:09
  • Oh yes, that must be it.
    – Alix Axel
    Oct 27, 2012 at 13:15

Look in Microsoft Windows 7 and 8's System Requirements.
There you can find answer to your questions when you see HDD requirements.


I had Windows 7 Ultimate 64-bit installed. I upgraded (ran the Win8 install within Win7) to Windows 8 Pro 64-bit. After the upgrade process was complete and ran disk cleanup to delete the "windows.old" directory and upgrade log files, I had at most 2.5GB more space used than before. The page file and hibernation file was the same as before. The Windows directory was about the same size. The partition at the beginning of the drive was still 100MB, not the 200-300MB number that people have been reporting. That must just happen with new installations.

Start8 is nice, it keeps Metro hidden. Windows 8 is nice too, doesn't take noticeably more space on an 80GB SSD and boots as fast if not faster than Windows 7. RAM usage seems a tad lower than with Windows 7. The "Deny or Allow" window box that appears when something wants Admin rights pops up quicker now, so they have tweaked that to operate quicker. In the past with low end machines, it took a lot of horsepower to darken the desktop (sandboxing or whatever). So Microsoft did think of efficiency when they developed Win8. Just let Metro be able to be hidden though.

  • Why are multiple people looking at the size of the Windows.old folder considering that folder includes more then just system files. Furthermore what does Start8 have anything to do with the author's question.
    – Ramhound
    Jan 24, 2013 at 12:10

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