The official system requirements for Windows 7 state that it requires 16 GB of space, or 20 GB for the 64-bit edition. Below that, it says that XP mode requires 15 GB more of space!

So, official specs say that a minimum of 35 GB are necessary, which would make affordable drives like this a no-go. That said, since 7 offers features for SSD like TRIM, and the pagefile can be moved to a physical hard drive, is it really necessary to have 35 GB of space? Bonus points if you have actual experience installing this kind of setup.

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    You don't have to place the XP Mode VM on your system partition. Commented Dec 16, 2009 at 4:06
  • I didn't realize that was an option... that makes it much easier!
    – Lifeson
    Commented Dec 16, 2009 at 21:33

5 Answers 5


Windows 7 Home Premium 32 bit takes 9 GB of disk space installed, but you will typically need a few GB for the pagefile (depending on how much RAM you have). If you don't plan on installing much on that drive, you should be fine with 30 GB. You can install XP on a different drive, so you should be fine there too...

I have a Windows 7 Home Premium virtual machine with 31 GB of disk, and it's been plenty so far (using 13 GB right now, after one month of usage...). But I didn't install a whole lot of programs there... no MS Office, nor Visual Studio etc...

So, in my case, I would have enough space even for the XP mode (but there's no point of running XP mode in a VM [besides fooling around or testing it]... so I won't do that). To sum it up: 30 GB will be enough, if you don't plan on installing lots of disk-hungry programs like MS Office and the like.

On the other hand, I agree with Tim too: I wouldn't install Win7 on anything less than 80GB for machines where I do need to install lots of disk hungry programs (or games:).

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    Perfect! I think games are going to be the bigger issue, but I will probably only have one or two major games, the rest of the data will be media on a separate drive.
    – Lifeson
    Commented Dec 16, 2009 at 21:47

I wouldn't recommend anything less than 80 GB for a boot drive on Windows 7 if you're going to use it as your main general-purpose PC. I've been running Windows 7 Professional 64-bit since it was released in late October, and two months later, I'm already using 36GB on my boot drive and I've only got 24 applications installed according to the "Programs and Features" dialog. (That's including no-brainers like the Flash plugin, etc)

Yes, you can redirect user folders and program files to another drive, but in my experience, it seems that a significant number of common system files will still end up on the boot drive whether you like it or not.

I'm going to wait a bit longer for SSD prices to drop before taking the plunge, myself.

  • Take the plunge! :) That will help drive prices down faster :) I've taken an Intel X-25M, I did pay quite a bit more than what I would have paid even today, but I don't regret it. It really pays off, especially for a machine that you use on a daily basis.
    – Zoran
    Commented Dec 16, 2009 at 5:54
  • You both raise good points to consider; I will consider a bigger drive, but I'm also willing to put forth some extra effort to optimize based on drive size.
    – Lifeson
    Commented Dec 16, 2009 at 21:44

well, a fully blown Windows 7 Ultimate installation requires much less than 10 GB, but you'll have to allow for 'growth' (WinSXS folder), you can also disable hibernation if you don't need it, this will free up a great chunk of disk space (the equivalent of your physical memory).

if that's not enough, you can rip unnecessary/unwanted components (e.g. drivers, languages, etc.) from your installation disk using vLite (this can reduce the installation size to less than 2 GB, ex. pagefile).

so, with a little tweaking, 30 GB should be good enough for what you have in mind.

  • "much less" is probably overstated... the 32bit Windows 7 does fit in under 10 GB, but that's without the virtual memory pagefile.
    – Joe
    Commented Dec 16, 2009 at 5:44
  • no reason to downvote, Joe, if you read the question more thoroughly. the OP states explicitely that virtual memory can be moved to a another disk, that's why i left pagefile.sys out of the equation. that AND the fact that the XP VHD doesn't necessarily have to reside on the system drives makes 30 GB a sufficient amount of disk space for this setup.
    – Molly7244
    Commented Dec 16, 2009 at 13:33
  • I'd be looking at Professional, not Ultimate, but 64-bit would make it a bit bigger. I appreciate the pointer to vLite and your tips, Molly!
    – Lifeson
    Commented Dec 16, 2009 at 21:38
  • even with 64-bit Windows, 30 GB is more than enough. and depending on what you want install in the XP VM you can even leave the VHD on the SSD and still have plenty free diskspace.
    – Molly7244
    Commented Dec 16, 2009 at 21:43

yeah 30gb ssd is enough, but if ur a computer guy like me and you wanna install windows on different drives like sd cards, you would at least need 15 gigabytes of storage on the ssd/sd/hdd with the page file. so for about 1 application, a 16gb sd/ssd/hdd would be enough, if u were just going to experiment with it in 32 bit mode.

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    oh, and your computer will be SUPER slow with 16gb. 30gb would be faster, but still the same kinda slow. Commented Nov 22, 2017 at 16:23

30 gig is not enough - should do at least 50 gig Dot net and C libraries can increase the size of windows a lot Many different software on the market requires these libs

But today the low cost of SSD drives are low enough to use 200 or more gig as a main drive. I imagine in a short time we will see higher reliability and even lower prices for these drives.

They can speed up your PC quite a bit. Not just in boot up time which is more than 3 times faster.

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