Microsoft

Pro tip: Override the 4GB memory barrier on 32-bit Windows 8.1 systems

Turn on Physical Address Extension mode and unleash the full potential of your 32-bit RAM memory.

50490C_Comal_Chip_Left_FINAL_pins_trans.jpg
Although the 64-bit transition period has come and gone, there are a surprising number of active installations of the 32-bit Windows operating system, particularly in industrial or business environments. One plausible explanation is the fact that backwards compatibility with older 16-bit Windows code is not possible on 64-bit Windows. Virtual 8086 mode, which is what NT Virtual DOS Machine or NTVDM relies on, cannot be utilized when the CPU is in 64-bit long mode. To counter this limitation, 32-bit Windows is used instead of 64-bit Windows.

Initially, there wasn't much of a difference between the two architectures in real world usage situations. However, over time, the base amounts of memory starting at 8GB and above exceed the maximum addressable memory space on 32-bit Windows, which is set at a rather paltry 4GB. And that doesn't even take into consideration reserved memory overhead that comes into play when you max out the system memory, sometimes bringing usable memory down below 3GB.

Some operating systems like Linux implement a feature called Physical Address Extension or PAE mode, which switches to 36-bit memory addressing, allowing for access to a grand total of 64GB of main system memory, which is a massive improvement. Likewise, Microsoft has implemented PAE in the Windows kernel, albeit disabled by default and only accessible on server editions of Windows. To that end, a proper patch of the Windows kernel will be necessary on desktop editions in order to attain the same memory access benefit.

a_WindowsPAE_1.png

With only 3.5 GB out of 8 GB of main memory available, that's just a sheer waste of potential resources

Aside from some notable exceptions, which will be mentioned in a bit, enabling PAE in Windows is a rather painless exercise with no harmful side-effects. Although you can address up to 64GB of memory in PAE mode, each process is limited to 2GB of memory space per active process. For certain memory hungry applications, like Adobe Photoshop, you are still far better off using a 64-bit version of Windows instead. For this reason, I would consider PAE mode to be more of a Band-Aid than an actual long-term solution. Luckily, for a good portion of business applications, this shouldn't be a major concern.


Also read: Five Windows 7 Gadgets to keep you informed about your system


Steps

Activating proper PAE mode on Windows 8.1 is a fairly easy process. However, before you begin the procedure, be sure that no RAM disk or memory optimizer drivers are active in order to prevent possible conflicts. You can re-enable them once you have successfully booted into PAE mode on Windows. For safety purposes and easy recovery, you will be creating a boot menu item so that you can go back and forth between PAE and non-PAE modes in case additional troubleshooting is necessary.

Here are the steps:

  1. Download the PAE Windows kernel patch from Wen Jia Liu's personal webpage.
  2. Enter the Desktop tile from the Start screen and open the downloaded zip file.
  3. Extract PatchPae2.exe to your System32 folder. The default location is C:\Windows\System32.
  4. Right-click on the Windows Start Button and click "Command Prompt (Admin)"
  5. Execute the following commands in sequence:

cd %SYSTEMROOT%\System32

PatchPae2.exe -type kernel -o ntoskrnx.exe ntoskrnl.exe

PatchPae2.exe -type loader -o winloadp.exe winload.exe

bcdedit /copy {current} /d "Windows 8.1 (PAE Patched)"

b_CMD.PNG

Windows generates a unique boot ID, referencing the PAE option.

At this juncture, you will see a message stating the entry was successfully copied. Write down the long string of letters and numbers surrounded by braces, representing the boot ID, since you will need to use it for the next few commands:

bcdedit /set {PASTE BOOT ID HERE} kernel ntoskrnx.exe

bcdedit /set {PASTE BOOT ID HERE} path \Windows\System32\winloadp.exe

bcdedit /set {PASTE BOOT ID HERE} nointegritychecks 1

bcdedit /set {bootmgr} default {PASTE BOOT ID HERE}

bcdedit /set {bootmgr} timeout 5

Once all the commands are processed, you will need to reboot your system for changes to take effect. When you reboot, you will be presented with a Windows boot manager screen. The time out is set to five seconds, but you can change this if you wish using the following command, replacing the X with the desired number of seconds for the timeout, a 0 to boot immediately to the default entry, or a -1 to make the timeout indefinite.

bcdedit /set {bootmgr} timeout X

c_WindowsPAE_2.png

When Microsoft pushes updates to Windows 8.1, it can sometimes include updates to the kernel itself. If this ever happens, simply run the following command to refresh the PAE kernel.

PatchPae2.exe -type kernel -o ntoskrnx.exe ntoskrnl.exe

And finally, if you wish to return Windows back to its former non-PAE enabled state, you may do so by performing the following tasks:

  1. Delete the boot entry for "Windows 8.1 (PAE Patched)" via msconfig.
  2. Delete the files ntoskrnx.exe and winloadp.exe from System32.

d_WindowsPAE_3.png

Ahh! Much better!

Caveats

With all this in mind, it's important to note that certain hardware drivers might not work correctly in PAE mode. Intel HD series graphics starting at around Sandy Bridge will experience video buffer corruption issues, since the drivers written for 32-bit Windows 8.1 do not take the extended memory addressing that is present in PAE mode into account. The only known workaround at this time is to force install the Windows XP 32-bit version of the Intel HD display driver.

Bottom line

Depending on your needs, this workaround works rather well for the most part, with the only major drawbacks being an uglier desktop with no Aero Glass transparency in the user interface. The reason for this is the fact that the driver is not written to follow the latest WDDM framework. Another major sticking point is that switchable GPU graphics like Nvidia Optimus are rendered useless when the host integrated GPU isn't running the correct drivers. This could very well be a make it or break it situation, especially if you have a work laptop that works in graphics heavy applications like AutoCAD. Dedicated, non-switchable graphics solutions from vendors like Nvidia and AMD are unaffected by the PAE limitation.

All that said, this PAE guide may still serve as a blessing for anyone clinging to legacy software, but might want to make the best use of all their system memory at the same time. Although 32-bit native Windows might not be around forever, there's still some life left in the flagging platform and you won't have to jump ship to 64-bit for the foreseeable future.

 

About

An avid technology writer and an IT guru, Matthew is here to help bring the best in software, hardware and the web to the collective consciousness of TechRepublic's readership. In addition to writing for TechRepublic, Matthew currently works as a Cus...

45 comments
Liam2978
Liam2978

HELP ME PLEASE, MY PC JUST CONTINUOS KEEPS BLUE SCREENING HELP ME!!!!!! I can't stop it, every time I restart it it blue screens, help me I'm desperate!

kenxu
kenxu

This won't always work. It is very much depends on what kind of device driver that you need to use and how good those drivers were written. This issue existed in XP days and became a more prominent issue since Vista. It is true that 32bit version of Windows 2003 and Windows 2008 can address more than 4GB because PAE is enabled by default. But that also impose a requirement to all the device drivers to play with memory address mapping nicely. Make it harder to develop the device drivers. So a driver certified for Windows 7 32bit doesn't necessary work well with Windows 2008 32bit. For example Intel HD Graphics driver doesn't have a version for Windows Server 2008. The driver wasn't designed with PEA in mind. So if you have a laptop with HD Graphics, you cannot use this patch (BSOD). I had 4 laptops in home, the patch works on two of them and not the other two.

AdityaL1
AdityaL1

how to type the second and the third command???????????

I am trying for days

it is telling the system cannot find the path specified

juancarlosgebhardt
juancarlosgebhardt

I've done step by step in detailed fashion, and every completed step in cmd (as administrator), it confirms me with (patched, successfully done, and bla bla bla bla bla), the problem, once I've finished, last step, reboot, or restart, ok ok, after that, ohhhhhhh surprise, nothing has changed, useless patch: (installed Ram 4.00 GB, Usable 2.99 GB), I've done it several Times and nothing, don't know why, is there any other or more reliable software out there to Enable PAE, or any other advice ???, thanks to anyone that can Help, and Regards, From Cuernavaca, City, Mexico
Cheers !!!

anser_perfect
anser_perfect

sir how r u doing....my question is related to this post. i have 64 bit hp notebook but i had to install 32bit windows8.1 on my machine so i followed you and it worked but after some time like 30 to 40 minutes i got the error about perhaps output visual issue and my system shutdown. i am not able to start my windows.i am trying to install another Microsoft OS but system says winload.exe problems....i am very confused. i am trying to get out of this but i can not find a way...is there any way to sort out this problem or i have to go to repair it.

doublet
doublet

where do i get this patch?

bwithage
bwithage

Does this mean I can up my physical RAM from 4GB to 8GB, or more, and it will all be recognized?


Gisabun
Gisabun

A note for some is that the patch also works on Vista and Win 7. Especially with Vista and earlier Win 7 computers sold, that they purchased 32-bit versions. What do you do in that case [OK aside from removing Vista and putting on Win 7]? Do you wipe your drive and re-install everything after adding extra RAM or use this?

carlsf
carlsf

And WHY WOULD?????

Sorry Microsoft but we will never be going Windows 8/8.1.

The UI is METRO and we dont want this style of UI anywhere near our business.

And unless your next release of Windows has a Classic style UI (Start Button and Menu) and has a 7 style UI then 7 will be our LAST Microsoft purchase. 

dhjohns
dhjohns

I have both Windows 8, and 7 Ultimate installed in natively bootable VHDs.  I have Windows 8.1 installed natively on my HDD.  Due to my MB (and processor with 8.1) 8, and 8.1 are both 32 bit.  W7 is 64 bit.  I use EasyBCD so my OS choices are in the Windows 7 boot menu.  After I applied the above patch to both Windows 8 and 8.1 I now have the option to boot into Windows 8, and 8.1 PATCHED OR UNPATCHED.  This patch works marvelously!

deICERAY
deICERAY

A lot of 32 bit systems still around - "One plausible explanation is the fact that backwards compatibility with older 16-bit Windows code is not possible on 64-bit Windows."

The other is that more rational people are not willing to keep paying ransoms to M$ for OS 'improvements' that aren't. Windows 8 is the most insulting software I have ever encountered, and I urge everyone to move to open source systems and stop the M$ madness - look to Munich!

ghughes
ghughes

Interesting...
Sophos blocks the wj32.org website because 'Mal/HTMLGen-A has been found at this website'.

matt
matt

The website updates the patch from time to time so make sure you download from there to get the latest and greatest version. Currently this patch works on Windows Vista SP2, Windows 7 SP0, Windows 7 SP1, Windows 8 and Windows 8.1. It may work on other versions but are either not recommended or not tested. You could always try it out (after backing up) and revert back if unsuccessful.

rla2680
rla2680

a visit to Wen's page answered the question. PAE works in vista, win7 and 8

rla2680
rla2680

does this PAE patch work for Win7?

Mark W. Kaelin
Mark W. Kaelin moderator

Are you using PAE for your 32-bit Windows systems? Do you have any problems to report? Has it been a notable success?

Razer_Angel
Razer_Angel

@juancarlosgebhardt Yah,because the 1.1 gb something goes to maybe your video card,I added another RAM strip to make my memory 8 gb and alas!there is one gb reserved for your system and video card.so try putting another strip of RAM and see the magic

AdityaL1
AdityaL1

@juancarlosgebhardt

how to type the second and the third command???????????

I am trying for days

it is telling the system cannot find the path specified

Matt Nawrocki
Matt Nawrocki

@Gisabun You will need to use the patch. Wiping everything and reinstalling 32-bit Windows doesn't change how it detects the extra memory.

Gisabun
Gisabun

@carlsf : Who's "we"? You? Ever heard of Classic Shell? Start 8?

dhjohns
dhjohns

@carlsf I guess you won't be making any more Microsoft purchases.  I am so happy that you will be the one missing out, and not me.  I guess you won't be buying any more computers either.  LOL

MrIcehouse
MrIcehouse

@carlsf  I can't see why people can't get the Modern interface it's just a large start menu
, and 8.1 you can boot to the desktop if you want, it's really not that difficult. Windows 8.1 runs faster than 7 or XP also. I have 7 on my desktop and I can't remember the last time I used the start menu, have 8.1 on laptop and have no issues with the modern interface.

thecactusman17
thecactusman17

@deICERAY Quit your whining, I've been using 8.1 for months, it's a huge upgrade over anything that wasn't Windows 7 and it's a pretty decent feature set even there.  Boo Hoo, your Start Button is gone, how about you sack up and start working with the new OS instead of whining like a child all over the internet.  I have yet to see a feature that wasn't either left identical to Windows 7 or improved in performance and function.


Also, 32 bit systems are still around because companies aren't willing to spend money when they can just blame the IT guys every time their copy of Windows 98 crashes in the middle of a Powerpoint presentation for a fraction of the cost.

Matt Nawrocki
Matt Nawrocki

@ghughes Sounds like an issue with the site. I know the PAE utility itself is clean.

Al_nyc
Al_nyc

@rla2680  I was wondering the same thing.  In my office they just started rolling out 32 bit win 7.  Who know if and when we will get win 8.1.

kenxu
kenxu

@Mark W. Kaelin Worked on two laptops Win7. Doesn't work with other two laptops has same Win 7 but with Intel HD Graphics. With Standard VGA driver, everything works. Intel HD Graphics Driver doesn't play nicely with PAE.

dhjohns
dhjohns

@Mark W. Kaelin It is a notable success.  Per my previous post I now have the ability to boot into either patched or unpatched.  I have tested it on 8 and 8.1 and it works flawlessly.

Gisabun
Gisabun

@Matt Nawrocki : You didn't understand my comment. Outside of patching, the only option to use the extra memory would be to wipe the drive and re-install Windows and apps.

carlsf
carlsf

@Gisabun @carlsf Why should we have to install another applicaion to get what should have been there from the start.

This is a business with 115 users, that is the "WE"

carlsf
carlsf

@dhjohns We do still purchase hardware only if we can get WIN7 and there are still venders who service NOTE SERVICE their clients with what they ask for.

Also we are trailing another O/S and it is only $NZ475.00 per system all the applications we need/require. Complete O/S, Applications and the Hardware venders supply the O/S installes ready to go, and we have to do very little to connect them to our network.

NOW that is service and not what MS dishes out.

DT2
DT2

@MrIcehouse I'm not sure one can trust any speed test run on Win-8. The OS was written without access to the hardware real-time clock on the motherboard.  That's because it's really a mobile OS and mobile devices don't have an RTC. Not sure if 8.1 fixed that or not, though.

carlsf
carlsf

@MrIcehouse The cost of going 8/8.1 with the upgrade to Applications, and in some cases hardware peripherials is (we have done the sums) NZ$1200.00 per system in use. this acounts for the 1) WNI8 disks and licence, 2)To upgrade the Applications we use office/accounting/graphics/communication etc... 3) tech time to complete the upgrade/installs 4) Training time to retrain users, and support, 4) Loss in productivity while this is happening.

Do you get the point as to why it is a NO GO. 

RNR1995
RNR1995

@MrIcehouse

Actually in the tests I have been running 7 x64 is just as fast as 8.1 x64
Ironically the 64 bit versions test faster than the 32 bit versions even on old hardware
What ever OS people run in their house in one thing but to deploy this bastard of an OS to a few hundred users, no thanks
Obviously the people at MS have never done remote support either
I just love logging into a 2012 server without a start menu, makes my job so efficient.....
startisback anyone?????

dhjohns
dhjohns

@Matt Nawrocki @dhjohns I just installed patch with Windows 7 x32, and it also works great.  No change except for recognizing all of the memory!

mickrussom
mickrussom

@thecactusman17 @deICERAY  If your precious 8.1 is so great, why cant it do skins. People who work a lot with computers doing WORK dont want stuff to move around and cause huge amounts of retraining. What a dolt. Scum at microsoft product management need to learn to SKIN the thing. Go ahead with your new GUI, fine, but leave it skinnable and no one will complain. Scum try and force change. SCUM. Unix shell is still similar to what it was in the beginning, 


See Version 7 unix from the 1970's

http://en.wikipedia.org/wiki/File:Version_7_Unix_SIMH_PDP11_Emulation_DMR.png


Look at it. Weep. Breaking stuff is not innovation, its the opposite. Dont break stuff. make new stuff. breaking old stuff or blocking access to old stuff is what stupid childish moron idiots do. 

Saskatoonian
Saskatoonian

@thecactusman17 @deICERAY Who do you think you are? Deriding somebody because they like hundreds of thousands others do not like the look and feel of Windows 8. Just because you have it and obviously like it, doesn't give you the right to put down the multitudes of us who don't like the look and feel of Win 8. I for one will stick with Windows 7, which I think is a great operating system, the best Microsoft has yet put out, and I've been working with Windows since 3.1! So if you don't agree with what someone has to say instead of putting them down like you did, keep your damned opinion to yourself!!

kitekrazy
kitekrazy

@thecactusman17   If Microsoft needs a shill, you should get hired.  Please cease your ignorance. I'd run Vista before Windows Ih8.

tenorman12
tenorman12

@thecactusman17 @deICERAY  

It's nothing like W7 and to me is a downgrade, not an upgrade, You can't do a dam thing with installing M$ programs on offer for free without logging in with your account all the time...a pain in itself so I just install in the normal Desktop option and forget the store. Thank goodness I still have W7 to fall back on. Roll on maybe W9 or 10

Matt Nawrocki
Matt Nawrocki

@Al_nyc @rla2680 Yes. This patch works for Windows 7. Instructions specific to Windows 7 are included in the accompanying readme file.

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