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My Windows 10 installation is 32-bits (x86). The official Microsoft documentation does not say whether PAE is supported on Windows 8, 8.1 or 10, only referring to earlier versions of Windows. Its not clear if this is an error in the documentation or not.

Other links, such as this on the Microsoft support forums or this offered an unsupported patch for PAE on Windows 10, are inconclusive or contradictory.

Does Windows 10 32-bit support PAE? How is it enabled so that more than 4GB of RAM can be addressed and used? Assume the motherboard chipset is modern enough to support PAE.

Hennes
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AlainD
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  • "PAE, or Physical Address Extension allows 32-bit operating systems the ability to use more than 4 GB of RAM. Currently the only supported editions of Windows that run on 32-bit OS with PAE and more than 4GB of RAM are Windows Server Editions (2000, 2003, and 2008). If you want access to more than 4GB of RAM and you don't run Windows Server, PAE isn't necessary and you simply need to run Windows 64-bit (Vista, 7, 8, 10, for example).">>>>>https://www.infopackets.com/news/9553/does-windows-10-require-cpu-support-pae – Moab Apr 06 '20 at 11:24
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    Windows 8 and newer requires a processor that supports PAE. The documentation only applies to Windows XP, Windows Vista, and Windows 7. Even with PAE you are still limited to only 4 GB system memory. How PAE works is extensively documented in other answers on this site. – Ramhound Apr 06 '20 at 11:26
  • Does your computer support 64-bit operating systems? If so back up and install the 64-bit counterpart to what you what. PAE (if you can do it) will not buy much on a workstation. – John Apr 06 '20 at 11:58
  • Reformating the HDD, re-installing 64-bit Windows and then re-installing all applications is an interesting suggestion but would be hugely inconvenient and, more importantly, does not definitively answer the question "Does Windows 10 32-bit support PAE?" – AlainD Apr 06 '20 at 12:29
  • @Ramhound: The installed processor is the i3-4340TE (https://ark.intel.com/content/www/us/en/ark/products/80918/intel-core-i3-4340te-processor-4m-cache-2-60-ghz.html). The processor is fast and modern and I would assume does support PAE...but it is not obvious from the Intel documentation. – AlainD Apr 06 '20 at 12:36
  • Going from meomry: "No, win10 does not support it anymore". Instead use a 64 bit installation (which is widely available since about 1996 in genral, and as per win7 for microsoft) – Hennes Apr 06 '20 at 12:48
  • i3 is not a real fast CPU and if you have a slow (5400-rpm) hard drive that was common with i3 processors, you may not gain much from added memory. – John Apr 06 '20 at 12:52
  • @Hennes: It would be good to get a definitive answer. Various Microsoft and Technet articles on this issue are not clear. The recommendation to re-install everything 64-bit is fine, but in my case is (a) not possible because this is a work-provided computer and I am remote from the IT department and (b) may not be possible at all because the computer has a small (28GB) HDD and a range of developer tools must be installed as well. The MS requirements page (https://support.microsoft.com/en-us/help/4028142/windows-10-system-requirements) states 20GB are required just for 64-bit Win 10. – AlainD Apr 06 '20 at 12:55
  • @AlainD - I can only go off the documentation that exists. That specific documentation explictily indicates it does not apply to Windows 8 or newer. However, I know for a fact, Windows 8 and newer require a processor that supports it. In fact, there was a question about Virtual Box where the author disabled PAE support for the VM and Windows 10 complained indicating it was required. – Ramhound Apr 06 '20 at 12:57
  • @John: This is not about gaining performance (the computer is fast, despite what you might think!). This is about not crashing the entire system when I have two instances of Visual Studio 2019 running with Chrome open as well...!! – AlainD Apr 06 '20 at 12:57
  • So I suspect the answer is going to be that the PAE mode is already enabled, which is the reason your actions, made no difference. As I have indicated even with supported versions of Windows PAE didn't allow more than 4 GB system memory. PAE mode will not prevent 32-bit processes from crashing if the amount of memory the system has installed is not enough. – Ramhound Apr 06 '20 at 12:59
  • @Ramhound: Understood, I'm wondering whether the MS documentation just needs updating with a definitive answer. As for PAE support, this i3-4340TE processor is fairly new, but how do you tell whether PAE is supported or not? The Intel documentation doesn't have a "PAE Support?" entry (or not that I could see). – AlainD Apr 06 '20 at 12:59
  • @AlainD - The documentation is already current. The documentation is current and only applicable to versions that were listed within the document. – Ramhound Apr 06 '20 at 13:02
  • @Ramhound: That's fair enough. It would be good if existing documentation was reviewed/updated when newer versions of the OS were released. In the example you linked to it might state, for example, that the documentation applies to Windows 8 and Windows 10. The silence on Windows 10 is at the very least ambiguous. My system appears to have DEP (Data Execution Prevention) enabled, which appears to imply that PAE is available. – AlainD Apr 06 '20 at 13:10
  • "The MS requirements pagestates 20GB are required just for 64-bit Win 10" That feels right. Running win7-x64 (OS plus open ofice + firefox + putty + a few others) from a SATA pendrive consumed about 20GB. – Hennes Apr 06 '20 at 13:12
  • DEP (and PEA_ might be required. But it is fair to assume that win10 >4|GiB only runs on x64 install, which are present on just about anything produced in the last decade. Exception might be old tablets with less then 2Gi|B memory. Almost no reason for anything not to use 64 bits |OS's in the last 15-ish years. – Hennes Apr 06 '20 at 13:14
  • @AlainD - Documentation with regards to Windows 10 has already been updated. The linked documentation does not apply to Windows 10. – Ramhound Apr 06 '20 at 14:24

2 Answers2

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My Windows 10 installation is 32-bits (x86). The official Microsoft documentation does not say whether PAE is supported on Windows 8, 8.1 or 10, only referring to earlier versions of Windows. Its not clear if this is an error in the documentation or not.

The linked documentation is current and explicitly only applicable to Windows XP, Windows 7, and Windows Vista. Windows 8 and newer require a processor that supports PAE/NX/SSE2. All modern Intel and AMD processors support PAE/NX/SSE2 since those extensions are required by all supported versions of Windows.

Does Windows 10 32-bit support PAE?

Yes, Due to the fact it's required in order to be installed. The processor requirements for Windows 8 and Windows 10 are identical. However, Windows version 1607 added one additional x86 extension requirement, but other than that, they are similar.

While the PAE/NX/SSE article does not explicitly indicate it applies to Windows 10, the processor requirements for Windows 10 version 1507 were identical, and the article does not expressly show it is not applicable. This means the information contained within the support article is implicitly applicable to Windows 10.

PAE/NX/SSE2 Support Requirement Guide for Windows 8

How is it enabled so that more than 4GB of RAM can be addressed and used? This is not about gaining performance (the computer is fast, despite what you might think!). This is about not crashing the entire system when I have two instances of Visual Studio 2019 running with Chrome open as well...!!

PAE mode was helpful in the case of something like an Apache/MySQL server, allowing the server to address more than 3 GB of memory, leaving the rest of the memory to the system. PAE mode only allowed 32-bit processes, the ability to address more than 3 GB. It did not allow more than 4 GB of system memory to be installed on a 32-bit installation of Windows.

PAE mode will not be helpful if you are attempting to run resource-intensive applications and your system does not have enough memory.

The recommendation to re-install everything 64-bit is fine, but in my case is (a) not possible because this is a work-provided computer and I am remote from the IT department and (b) may not be possible at all because the computer has a small (28GB) HDD and a range of developer tools must be installed as well.

However, based on the system's workload, installing Windows 10 64-bit is most defiantly the solution to your problem. Of course, you would still need to install more than 4 GB. The fact that it's a company-provided computer does not change the fact that a 64-bit version of Windows 10 is the solution to your performance problems.

Ramhound
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  • Good answer...but doesn't this (https://docs.microsoft.com/en-gb/windows/win32/memory/physical-address-extension) contradict the affirmation PAE...did not allow more than 4 GB system memory? In the link, the article explicitly says "PAE allows the operating system to access and use more than 4 GB of physical memory". – AlainD Apr 06 '20 at 13:30
  • @AlainD - PAE does not change the amount of virtual address space available to a process. Each process running in 32-bit Windows is still limited to a 4 GB virtual address space. - No; It doesn't actually. When you consider that without PAE a 32-bit process could not address more then 2 GB, being able to access another 2 GB, was amazing when a process needed it in 2009. – Ramhound Apr 06 '20 at 13:32
  • You may be answering a question that is not being asked. I accept there is a per process limit in x86 Windows of 2GB (or 3GB with some extensions). I don't need more than 2GB per process, but > 4GB for many processes. Modern, resource intensive applications like Visual Studio 2019 consume (say) 0.5GB of memory according to Task Manager. Start several instances of these apps and you run out of memory, even while staying well within the 2GB limit per process. The Microsoft documentation appears to suggest it is possible to address and use more than 4GB, provided PAE is supported. – AlainD Apr 06 '20 at 13:40
  • @ The OP: how about this? In command line (admin), duplicate your current OS (Windows 10 x86) line, and add the "/PAE" argument at the end, preceded by a space, like this: "bcdedit /copy {current} /PAE ". This will add an entry to your boot menu, and you'll have the option to boot from your regular Windows 10 x86 with or without PAE "enabled". If your PC crashes for some reason, you'll know that your platform is better-off without PAE, and you can delete the additional line in the boot menu. If your PC performs better with PAE enabled, then set it as default. –  Apr 06 '20 at 14:05
  • Downvote because not answering the question and some statements are misleading. PAE should help a 32 bit OS to utilize up to 64 GB RAM (if present) if no single process needs more than 4 GB. See 32 bit Linux for example. OPs request to have it's two IDEs and a Browser combined RAM usage to exceed 4 GB is completely valid. – thomas Apr 09 '22 at 17:49
  • @thomas - I actually answered all three questions the author asked. PAE absolutely cannot allow a 32-bit install of Windows 10 use 64GB. My answer is limited to Windows 10 for obvious reasons, the question is limited to Windows 10 – Ramhound Apr 09 '22 at 20:45
  • I will remove my downvote (have to wait because SO wants it so) but still unhappy about pointing to microsoft docs saying Win10 is actually requiring a PAE processor (I guess implicitly because "modern" ones always have it). Yet 32 bit Win10 is artificially restricted so you can't use PAE. Statements like "PAE mode will not be helpful" aren't helpful at all. Still not lovin this answer... – thomas Apr 10 '22 at 15:09
  • @thomas - I don’t actually care about the downvote. I care that you said I didn’t answer the authors question despite addressing, every question the author asked. Nobody else felt the need to submit a different answer. I didn’t believe PAE was the author’s solution in 2020 not do I believe it’s a solution to his problem in 2022. PAE was great for a time, to allow powerful 32-bit processors, to allow applications to allocate more then 3 GB. I cannot answer unasked questions. The author wanted to know if Windows 10 supports PAE, I explicitly indicated, that is indeed the case. – Ramhound Apr 10 '22 at 15:32
  • There are hacks out there which claim to make PAE usable in Windows 10. I installed 32 Bit Windows 10 in Qemu/KVM and gave it 6 GB RAM. For my use case I saw no reason at all to install 64 Bit Windows 10. But limiting the Application to 3,5 GB minus what also runs appart from the applications I really want to run is a show stopper for me. I've no problem with applying hacks though. I worked around the problem by deleting the VM and sticking to wine. There is also no mention of the problem stemming from license policies of Micro$oft in your answer. – thomas Apr 10 '22 at 16:07
  • @thomas - Sounds like a potential answer. I am not going to suggest a hack. There are security ramifications. This was a work computer the author was using. I have answered many questions, solving many "catastrophic issues" caused by using applications that modify Windows system files. I was answering the author's question first and forthright. If I helped somebody else great, but that is only a secondary goal when I answer a question. I don't believe the licensing policies is relevant to the author's question. – Ramhound Apr 10 '22 at 16:14
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To add to the current answer, but in a more blunt way:

Although PAE is always enabled, MS adds a licensing limitation for all modern non-server editions of Windows so you can only use 4GB. See http://www.geoffchappell.com/notes/windows/license/memory.htm.

If you look at the source code of your patch, it does exactly what the author of that article did: it goes to the license-reading functions and puts a bigger limit there. Apparently it's not exactly up-to-date with current Windows 10…

Mingye Wang
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