How much more RAM does Windows 7 use than Windows XP?

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?

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).

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.

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.