I'm trying to figure out whether I need to go with the 64-bit version of Windows 7. I'd rather not, unless there's a big benefit, because even one or two missing 64-bit drivers or one app that doesn't work quite right wold be a lot of work.

The biggest reason to go with the 64-bit Windows 7 that I can see, is that it allows the use of more RAM. But I never max out my RAM now (despite simultaneously burning CDs, testing software in Virtual PC, with Windows 7, no less, and editing a document in Microsoft Word).

Since Windows 7 has a minimum RAM of 1 GB, (compared to something like 64 MB for XP) that suggests that Windows 7 uses a lot more RAM. So, how much more RAM does Windows 7 use than Windows XP?

  • Just assume that there is no 32-bit version. Now every hardware manufacturer wishes that were the case because they must make their hardware work under both given that people are not all upgrading. – dlamblin Nov 26 '09 at 18:49
  • 2
    if you don't have more than 4 GB RAM, i'd stay away from Windows x64. there are no real benefits (and certainly no 'performance boost') unless you have to address RAM beyond the 4 GB threshold. – Molly7244 Nov 26 '09 at 18:52
  • Oh, btw, Windows 7 runs just fine with 512MB of RAM. Don't believe me? run Windows 7 in a VirtualBox VM with that amount of RAM, runs smoothly. – Harley Watson Nov 26 '09 at 20:26
  • 1
    ya well, but you will not run much else, nevermind 'smoothly', in your virtualbox :) – Molly7244 Nov 27 '09 at 0:18

Do you have more than 2GB of RAM?

Yes? Then stop caring!

XP and 7 use RAM in different ways. Right now on my Vista box (Which has a lot in common with 7), I'm idling at 54% used RAM. That leaves me with under a GB! That's not enough left to, say, play Crysis. So let's turn my page file off. Very little change. Let's go play crysis anyway.

Ran great, and now I'm idling at 30% RAM. Vista and 7 cache in your RAM, because it's about 40 times faster than most hard drives (not SSDs though, it's still a lot faster, but not as much), so it makes a lot of sense to use it to speed up your PC.

If you have less than 2GB of RAM, stick with XP. Vista and 7 are much, much faster than XP if you give them modern hardware.

As for the minimum, XP never really ran well on 64mb of ram, and win7 can run on much less than 1gb. Seems like MS have changed their mind about how they want their OS to be seen. Back when XP existed, fewer people had PCs, and there was almost no widespread internet, so they could (basically) lie on the packaging and nobody would mention it. Now they've put a reasonable figure that will allow Win7 to run as designed (caching and all).

  • 3
    "Stop caring" is not an answer. – trlkly Nov 9 '13 at 19:32
  • @trlkly: Yes, it is, because asking whether XP or 7 uses more RAM on a machine with a modern quantity of RAM is asking the wrong question. – Phoshi Nov 11 '13 at 9:21
  • 1
    That is not for you to decide. The entire point of Stack Exchange is that we answer the questions given. It is not a conversational forum. The question was not "give your advice on updating to Windows 7, but specifically how much more memory one uses than the other. – trlkly Nov 18 '13 at 13:41
  • @trikly: It's a well known phenomenon that people do not always ask the questions they actually want the answer to. Which OS uses the most RAM is the wrong question under the constraints given, because answering it gives you no useful information. The question that's useful to answer is which one is more performant given some quantity of RAM. – Phoshi Nov 18 '13 at 13:57

Using more RAM is not really a bad thing. Sure, the OS may use a bit more ram for larger OS images, but the real reason is that Windows 7 has far superior cache and prefetch performance compared to XP.

In general, if 90% of your RAM is sitting there unused, then your computer isn't taking advantage of the memory it has. While it's true that Windows 7 needs a bit more RAM to run properly, the real truth is that it will take full advantage of the RAM you give it, unlike XP.

Windows 7 will function just fine with less than 4GB of RAM, so you should be fine getting the 32-bit version. You just won't do quite as much caching as someone who had 64-bit and more RAM.

That said, frankly I think it's worth getting 64-bit. Many of us used XP for 8 years or more, so it's not far-fetched to think we might be on Windows 7 for five years or so. It's obvious that 64-bit is where computing is now. I'd rather replace a component that doesn't have 32 bit drivers than use a 32-bit OS just for that piece of hardware. On the application side of things, through Windows on Windows (WOW), there should be no issues with 99.999% of 32-bit applications running on 64-bit Windows. The application would have to be doing things in pretty stupid ways to be tripped up.

  • Unless Using more RAM means you must buy more RAM, then it is a bad thing. – dlamblin Nov 26 '09 at 18:42
  • "In general, if 90% of your RAM is sitting there unused, then your computer isn't taking advantage of the memory it has." so, if we reverse this logic then your computer is only taking advantage if the operating system is doing "something" (i.e. shoving/caching data into RAM that may or may not be used for future user interaction) with the currently unused memory. :) – Molly7244 Nov 26 '09 at 18:45
  • I'd rather my PC be potentially speeding up than doing nothing at all :) – Phoshi Nov 26 '09 at 19:02
  • @dlamblin With RAM prices these days, I disagree. In addition, caching doesn't mean you "have to" buy more RAM, just that more RAM will benefit you. – phoebus Nov 26 '09 at 19:04
  • @Molly As long as that behavior isn't having a detrimental impact on performance, of course:) – phoebus Nov 26 '09 at 19:05

7 Home will idle on as little as 275mb of RAM. The O/S needs a good bit more than this to support the usual services and extras that most people will be using (or allow to run), as well as to (put in layman's terms) "do it's thing". The "average" 7-Home user will generally require about 600-650mb of RAM for W7 to load up everything that it's using and to be able to (again in layman's terms) "move around" without any bottlenecks or other slowing down.


Depending what I'm running, I'm constantly at either 800mb or 1gb in idle. Whereas in WinXP it was somewhat between 500-800mb.

But then again, I'm running with 4GB (3.5gb effectively since I'm on 32bit) so the extra 500mb are negligible.


Google Tweak-XP Pro. It allows you to change the amount of ram WinXP caches, up to 1GB. If you don't want the pagefile, make it down to 2MB[minimum].

  • 1
    Don't make your page file small, it will slow it down. Read the sysinternals articles by Mark Russonivich. – Rich Bradshaw Oct 9 '10 at 21:36

"testing sw in Virtual PC (Windows 7 no less)"

That reason alone, I'd be going with 4GB of RAM, which means 64-bit. XP lies to you about how much RAM you are using. It actively pushes data out of memory and into the page file when it's idle, even when you have memory free. 7 on the other hand actively caches data into your free memory space that you may potentially use, since MS smartened up and realized there's no reason for it to not be there. Having "free" memory is a waste.

Does the core XP OS use less RAM then 7? Yes. But it's all the other software that people install and run that really makes a difference in how much RAM gets used.

In short, do the basic research, and see if your hardware has Win 7 x64 drivers available. As for your software, I have yet to encounter something that doesn't work. The only thing I'd think to be worries of is if you're running some software that work with the hardware at a really low level. If it looks like x64 will work, use that.

Also, how do you plan on purchasing your upgrade? Retail upgrades give you the option of doing either 32 or 64 bit as you see fit. So you can upgrade to Win7 x86 now, and if you purchase more RAM later, you are still licensed to run the x64 version. You'll just have to do a re-install.


Molly (i think) i installed windows 7 on one partician and xp pro on the other partician on my dell lap top. I'm using 512 m of ram on a 64 bit machine. True, I need much much more, but both do seem to run alright. With windows 7 though, you have to be very careful about over loading it because it WILL freeze up. But for ordinary use, 512 is fine and generally 7 is alot better than xp. And (pardon my french) and hell, windows 98 was better than vista.

  • sure, for the fon of it, you can install XP on a 7 MHz machine with only 20 MB RAM :) winhistory.de/more/386/Screenshot8mhz_system.gif – Molly7244 Nov 28 '09 at 18:06
  • I'll try that some time. Only problem would be, it would probably take a month to install. Well, gotta go find that 20 meg memory chip. Hope you had a great Thanksgiving! clif – clif lawrence Nov 28 '09 at 18:16
  • our turkeys are safe ... at least for another few weeks :) – Molly7244 Nov 28 '09 at 18:52

Not the answer you're looking for? Browse other questions tagged or ask your own question.