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Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

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Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#21

Post by nivertech »

ajross wrote: post #8
0x0 wrote: post #6

There is also a very recently developed middle ground, the Linux "x32" ABI, since Linux v3.4: http://en.wikipedia.org/wiki/X32_ABI As I understand it, this mode gains performance by sticking with 32bit pointers in user-space instead of 64bit pointers, while still allowing for taking advantage of all the new registers etc available in x86-64 ("amd64") CPUs. (Many programs doesn't really need more than 4gb virtual addr…

x32 is clearly a good technical solution. If you're running on a 64 bit kernel, x32 is superior to i686 in every measurable way. But it's also yet another architecture. It's not binary compatible with either i686 or x86_64. You need your whole userspace compiled to use it. Middleware with embedded assembly (there's a surprising amount of this in glibc, and of course things like ffmpeg, libjpeg, etc...) needs to be po…

x32 is useful for VM-based languages: Java, Python, Ruby, Erlang, etc.

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#22

Post by masklinn »

Symmetry wrote: post #18
virmundi wrote: post #14

This seems like an appropriate place to ask this question. At work I have an i5 with 8 GB of ram. Unfortunately we're stuck with XP 32. So is there a away for me to use more memory over all? Specifically I have to have Outlook and my VirtualBox Linux machine running at the same. I'd like to use bank switching or PAE to give my VM 4 GB. While all of the other applications just fight out for the remaining 4.

No, only Windows server editions have PAE enabled and AFAIK this isn't something you can use without kernel support.

Technically, all modern Windows versions have PAE enabled (the NX bit requires enabling PAE for instance), but Windows adds license-based memory restrictions on top of that.

That's how the 2GB limit on Starter, the 4GB limit on non-server and the various limits on server editions are implemented.

And there is a kernel hack/patch to lift that restriction, although it is of course fully unsupported: http://superuser.com/questions/52275/how-can-i-enable-pae-on...

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#23

Post by thechut »

I dual boot Ubuntu 12.04 32-bit and Windows 7 32-bit on my HP laptop, it has 8GB of RAM. When I am running Ubuntu I see 7.8GB (I'm assuming this is 1000 vs 1024 issue and doesn't concern me) in my system settings and resource monitor. When I am running Windows I only see 3.8GB of RAM in resource monitor, but I see the full 8GB if I look in device manager. Can somebody explain this to me?

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#24

Post by floody-berry »

Mara wrote: post #9

Am I missing something, or does the top answer not address the question? Memory tricks aside, it seems the questioner is asking whether the physical RAM itself will ever be used. Short of PAE, unless my understanding is wrong, I was under the impression that the answer to this is no.

Even with PAE, many Windows versions hard limit the available RAM to 4GB (or less). So his answer isn't even correct given the reality of many operating systems & hardware.

http://en.wikipedia.org/wiki/Physical_Address_Extension#Oper...

http://en.wikipedia.org/wiki/3_GB_barrier

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#25

Post by virmundi »

masklinn wrote: post #22
Symmetry wrote: post #18

Earlier quoted context omitted.

No, only Windows server editions have PAE enabled and AFAIK this isn't something you can use without kernel support.

Technically, all modern Windows versions have PAE enabled (the NX bit requires enabling PAE for instance), but Windows adds license-based memory restrictions on top of that. That's how the 2GB limit on Starter, the 4GB limit on non-server and the various limits on server editions are implemented. And there is a kernel hack/patch to lift that restriction, although it is of course fully unsupported: http://superuser.co…

Thanks for the info. It's sad that I out my employer will allow it.

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#26

Post by riffraff »

nivertech wrote: post #21
ajross wrote: post #8

Earlier quoted context omitted.

x32 is clearly a good technical solution. If you're running on a 64 bit kernel, x32 is superior to i686 in every measurable way. But it's also yet another architecture. It's not binary compatible with either i686 or x86_64. You need your whole userspace compiled to use it. Middleware with embedded assembly (there's a surprising amount of this in glibc, and of course things like ffmpeg, libjpeg, etc...) needs to be po…

x32 is useful for VM-based languages: Java, Python, Ruby, Erlang, etc.

I am not sure this is true generally: the JVM has been able to use "Compressed OOPS" aka 32bit pointers to objects managed by the VM in 64 bit platforms for a few years, even without any support from the OS.

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#27

Post by untog »

thechut wrote: post #23

I dual boot Ubuntu 12.04 32-bit and Windows 7 32-bit on my HP laptop, it has 8GB of RAM. When I am running Ubuntu I see 7.8GB (I'm assuming this is 1000 vs 1024 issue and doesn't concern me) in my system settings and resource monitor. When I am running Windows I only see 3.8GB of RAM in resource monitor, but I see the full 8GB if I look in device manager. Can somebody explain this to me?

I'm not an expert on these matters, but as I understand it, Windows is not ignorant of the fact that you have 8GB of RAM, it is simply unable to address it. So it makes logical sense that it would show you having 8GB, but only 3.8GB of usable RAM.

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#28

Post by zokier »

thechut wrote: post #23

I dual boot Ubuntu 12.04 32-bit and Windows 7 32-bit on my HP laptop, it has 8GB of RAM. When I am running Ubuntu I see 7.8GB (I'm assuming this is 1000 vs 1024 issue and doesn't concern me) in my system settings and resource monitor. When I am running Windows I only see 3.8GB of RAM in resource monitor, but I see the full 8GB if I look in device manager. Can somebody explain this to me?

Most likely your Ubuntu uses PAE, and Windows does not. NT kernel certainly supports PAE, but likely MS has disabled it in client systems for some reason.

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#29

Post by AD1066 »

Holy Baader-Meinhof phenomenon. I ordered 8 GB of RAM for my HP laptop last night and spent well over two hours reading about this exact subject to see if I needed to install Windows 64-bit when it arrives. I think I even stumbled upon this same page.

That being said, I still don't fully understand; Once I install the new RAM, will I only receive the benefits if I perform a new 64-bit install of Windows 7, or will upgrading just amplify the benefits? (I currently have 3 GB in 1 GB + 2 GB as the default factory configuration.)

Sorry if this question is dense of me, but my field is economics and the more technical aspects of HN are often lost on me

Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?

#30

Post by 3amOpsGuy »

thechut wrote: post #23

I dual boot Ubuntu 12.04 32-bit and Windows 7 32-bit on my HP laptop, it has 8GB of RAM. When I am running Ubuntu I see 7.8GB (I'm assuming this is 1000 vs 1024 issue and doesn't concern me) in my system settings and resource monitor. When I am running Windows I only see 3.8GB of RAM in resource monitor, but I see the full 8GB if I look in device manager. Can somebody explain this to me?

>> I'm assuming this is 1000 vs 1024 issue

It'll likely be your graphics card uses a portion of your main RAM for its memory. This is common.

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