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

Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by thechut on Saturday July 14, 2012 @11:00AM (#4244333)
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?
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by plorkyeran on Saturday July 14, 2012 @01:00PM (#4244687)
It is a licensing restriction. Windows Server supports up to 64 GB on 32-bit versions: http://msdn.microsoft.com/en-us/library/windows/desktop/aa36...
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by 3amOpsGuy on Saturday July 14, 2012 @12:08PM (#4244530)
>> 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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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by cookiecaper on Sunday July 15, 2012 @01:38AM (#4246246)
I'm not sure this is true for discrete cards. Onboard GPUs will utilize good chunks of system memory (and this is configurable in the system BIOS generally), but discrete cards don't use any afaik.
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by ajarmoniuk on Saturday July 14, 2012 @12:33PM (#4244618)
It has been said here before. Linux fully supports PAE whereas Windows only uses it for execution restriction. Therefore you are not able to see anything beyond the 4 GB limit on Windows.
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by masklinn on Saturday July 14, 2012 @01:36PM (#4244811)
> Linux fully supports PAE whereas Windows only uses it for execution restriction.

That is not correct. Windows also supports full PAE, but adds licensing-based restrictions. The Datacenter and Enterprise editions of Windows Server 2008 will provide access to all 64GB RAM PAE can provide.

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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by thechut on Saturday July 14, 2012 @12:47PM (#4244656)
Sorry, didn't see it. Thanks for your response, that makes sense!
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by cdr on Saturday July 14, 2012 @01:59PM (#4244883)
You might be interested to know that Windows keys don't discriminate between 32-bit/64-bit. If you can find installation media for the same type of x64 distribution (Home, Pro, etc) as your 32-bit, you can install x64 and use your current key. May be worth the reinstall to get access to your RAM.

Of course, you might make sure that appropriate drivers for your laptop exist for x64. I would hope any laptop that can accommodate 8GB would have x64 drivers.

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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by zokier on Saturday July 14, 2012 @11:42AM (#4244444)
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.
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by masklinn on Saturday July 14, 2012 @01:40PM (#4244824)
> NT kernel certainly supports PAE, but likely MS has disabled

Nope. They can't actually disable it since the NX bit requires that PAE be enabled.

The limitation comes from licensing and tiering, and is handled in the kernel independently from PAE.

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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by untog on Saturday July 14, 2012 @11:28AM (#4244406)
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.
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by masklinn on Saturday July 14, 2012 @01:38PM (#4244815)
That is not correct, Windows is actually fully aware of the physical RAM on the machine and is technically able to use it, but has a license-based restriction scheme only letting a subset of the RAM be used.
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Re:Can a 32-bit OS machine use up all 8GB RAM + 20GB page file? by listic on Sunday July 15, 2012 @08:16AM (#4246804)
> I'm assuming this is 1000 vs 1024 issue I think rather some of the address space has I/O ports mapped to it, both in Windows and Linux.
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