How to Enable More Than 3.5 GB of Memory in 32-Bit Windows Vista
Disclaimer: Some have said this works, while some have said it doesn’t. This tutorial does not guarantee successful results.
You’re probably wondering why I picked a number as horrible as 3.5GB? Why not 4GB? Well, there’s a really technical explanation for this but to make a long explanation short, 32-bit operating systems can only handle up to 4GB of memory. In fact, this number may vary but I stuck with 3.5 GB. Along with the RAM, you also have other memory-mapped devices such as your video cards. The memory used counts towards the 4GB virtual memory address capacity of a 32-bit operating system. But actually, the world does not end at 4,096 megabytes for 32-bit Windows Vista users anymore because the Arsgeek is here to save the day.
If you’ve accidentally bought 4GB of RAM, this may be a good idea. And I say may because many 32-bit operating systems begin to lose efficiency as they surpass the 4GB mark. For that reason, if you have less than 3GB RAM, it’s not necessarily the best idea to go out and buy some more RAM. If you want to utilize more RAM (between 8GB and 128GB), you can always switch to 64-bit Windows Vista. Alright, enough babbling. Let’s get started.
Steps:
1) Access cmd: Click on the Start Pearl > type cmd in the Search Bar > and press Ctrl + Shift + Enter (this allows you to run cmd in administrative mode)
2) Type BCDEdit /set PAE forceenable
“BCDEdit is a boot configuration editor for the command line. Using the above command you’ve just enabled Physical Address Extension (PAE) which can address memory larger than 4 GB. ” - Arsgeek
Source: Arsgeek
Still need help? Check out our new forums where you can get an even faster and better response!
March 29th, 2007 at 8:36 pm
Here I am to save the day! I feel like I should make up an ArsGeek cape. And maybe some pocket protector shields.
Great site you guys have here. Keep up the good work!
AG
April 3rd, 2007 at 5:13 pm
I heard there was a disadvantage in using Physical Address Extension (PAE). Is that true?
April 3rd, 2007 at 5:43 pm
That shouldn’t be the case. However, you can say that there is not much of an advantage gained from this. I posted this tip for those who already have 4GB of RAM
April 5th, 2007 at 1:59 pm
Hi all !
Tested with Asus P5P-Deluxe and dont work for me !!
Memoy remap enabled in bios.
I must return with Vista-64bit.
April 5th, 2007 at 6:15 pm
Ya. I recommend you use 64bit. As for why it doesn’t work, did you run cmd in admin mode?
April 10th, 2007 at 7:59 am
Hi all !
Command executed with pure administrator account.
When i type bcedit it can see that pae is enabled
Vista 64 do not have response time like 32 bit version due the number of mixed 32/64bit dll.
April 11th, 2007 at 2:48 pm
Hi all !
I’ve read some post on different forum and nobody reported that this tips work !
There is some news here ?
April 11th, 2007 at 3:35 pm
It has worked for a few people including Arsgeek. Which forum?
April 13th, 2007 at 2:26 am
[...] How to Enable More Than 3.5 GB of Memory in 32-Bit Windows Vista Supposedly a way to extend the amount of usable RAM beyond 4GB on a 32-bit system using 'Physical Address Extension' (PAE). It's unclear from the comments whether anyone has really gotten this to work. (tags: RAM Memory PAE) [...]
April 17th, 2007 at 11:29 am
Hi all !
I dont know where im wrong !
Ive looked again on various french and english forum and this tip dont work as expected for some people.
Forum: Guru3d, Presence-pc, Hardware.fr,……
April 17th, 2007 at 4:00 pm
Mfck: I think you’d be better off with 64-bit Windows Vista
April 19th, 2007 at 2:07 pm
Peace people
We love you
April 28th, 2007 at 12:33 pm
I have one question on the amount of RAM for 32 bit VISTA. When I install my 4 GB of memory, my resolution options change for my video drivers. I can’t even select my native resolution of 1680×1050. But when I just use my 2GB of memory, it will show back up! Is this normal?
April 28th, 2007 at 1:15 pm
This is really weird. I suggest you visit http://www.tech-forums.net for help.
April 28th, 2007 at 1:59 pm
Thanks Albert, I’ll give that a try.
May 5th, 2007 at 5:55 am
does anyone have any idea of how to view memory usage in vista
you can give your pc more virtual memory in any version of vista by enabling miore in
SYSTEM
ADVANCED SYSTEM SETTINGS
ADVANCED TAB
PERFORMANCE SETTINGS
ADVANCED TAB
CHANGE
AND SETTING MORE MEMORY
BUT! CAN! I! VIEW! MY! VIRTUAL! MEMORY! USAGE!
May 7th, 2007 at 5:04 pm
Another vote for “Doesn’t work”. Advanced user (admin) here. Followed these instructions exactly and definitely did not have any effect.
May 9th, 2007 at 5:51 pm
Am plannig to try this…but if it doesn’t work, how to I reverse it? i.e., is there a way to “undo” the “Type BCDEdit /set PAE forceenable” if it doesn’t add to my memory?
May 16th, 2007 at 6:28 am
To undo, just type “BCDEdit /deletevalue PAE” , this will remove the added PAE settings.
May 21st, 2007 at 11:10 pm
too bad it doesn’t work for me too :(,
I have Vista Home premium 32 bit and my bios detects 4096 MB or something similar and Windows detects only 3071 MB no matter if I have remapping enabled or not and if I have PAE on or off(by the way I have 2 remapping option - hardware and S/W). Isn’t there any way to enable all available memory in Vista?
May 21st, 2007 at 11:17 pm
I guess it’s not possible
http://support.microsoft.com/kb/929605
May 22nd, 2007 at 4:10 pm
[...] (this allows you to run cmd in administrative mode) 2) Type BCDEdit /set PAE forceenable link: How to Enable More Than 3.5 GB of Memory in 32-Bit Windows Vista · Vista Rewired If you do heavy video edition, 4GB will give you a nice performance bump and since Vista is a [...]
May 25th, 2007 at 7:02 am
Hello friends.
Please tell me if I can use all my 4 GB RAM in 32 bit Vista with a 32 bit processor or not?
DO reply
Regards& Thanks
gp.singh.tech@gmail.com
May 29th, 2007 at 11:20 pm
sorry there, but i have not had an increase of ram above 3.328gb. i will continue to read up on further development with pae. i am sure there is some form of patch to allow for a full access of 4.096gb.
May 30th, 2007 at 5:29 am
you can give your pc more virtual memory in any version of vista by enabling more in
SYSTEM
ADVANCED SYSTEM SETTINGS
ADVANCED TAB
PERFORMANCE SETTINGS
ADVANCED TAB
CHANGE
AND SETTING MORE MEMORY
BUT THERE IS NO WAY OF CHECKING HOW MUCH VIRTUAL MEMORY WE ARE USING
June 1st, 2007 at 2:27 am
I Love you girls
Buy
June 4th, 2007 at 6:41 pm
Hi Jim. Photos i received. Thanks
July 6th, 2007 at 12:45 pm
by the way there are many websites that talk about this. 32bit can only address up to 4gb. when you only show 3.2??? that means you have 4gb of ram but your 512mb video card needs room in that 4gb of space so it takes 512 off the ram so it can be seen. other cards and drivers will take away more. This is one article there are literally hundreds of articles stating the same, even from Microsoft.
http://chris.pirillo.com/media/2007/05/23/4gb-memory-problems/
July 17th, 2007 at 3:32 pm
[...] How to Enable More Than 3.5 GB of Memory in 32-Bit Windows Vista ? Vista Rewired __________________ [...]
July 23rd, 2007 at 9:09 am
You wll not see all 4bg or ram! “I’m Right” is RIGHT!! Memory Adrress must be allocated to video cards and such. Vista is not Server OS like 2003 so the the PAE switch does not work due to DEP limatations with certain hardware/software…
August 7th, 2007 at 9:01 pm
This tip does not work.
PAE was enabled upon installation on three machines where I installed Vista Ultimate, no tweak needed. It seems Vista knows when there is more than 3GB, and makes adjustments at install time. All three machines had 4096MB of ram. One machines was DFI-based (AMD Athlon X2 + nVidia chipset) with a 256MB ATI card, BIOS reports 4096MB, Vista Reports 3.75GB. The other 2 machines were Gigabyte-based (Intel Core 2 Duo + GA-965P-DS3) with 256MB nVidia 7900GS, BIOS reports 4096MB, Vista reports 3.50GB
It seems Vista does not know how to map 36-bit addressing properly, because PAE usually means being able to use up to 8GB of RAM on 32-bit OS, as was the case with Server 2003 Enterprise with /pae. (I know, I tried it in Server 2003).
Solution? None really. Unless you want to buy Server 2003 Enterprise to watch your DVDs and play Spider Solitaire, which is a waste of money. Also, getting 64-bit Vista allows you to see all 4GB or RAM (I tried this too. Confirmed on both Gigabyte and DFI boards) but if your applications are 32-bit (ie Photoshop CS3, Premiere Pro CS3), they all can access around 2GB of the 4GB as well, which is worse. And there is no AWE (so no /3gb or /pae) in 64-bit Vista (pls correct me if i’m wrong). Nevertheless, unless your apps are true 64-bit, you’re stuck with these memory limits.
August 14th, 2007 at 4:58 am
Hello, Admin! You are the best!!! Congratulations. Best regards from regular visitor of your site.
September 19th, 2007 at 5:21 am
Well……….there are ups and downs and not sure if this works… haven’t yet tried hope this works!! wish me luck!
September 19th, 2007 at 8:22 am
I think this is a problem with Vista and some form of product protection or security or something. (Grasping at straws) I have tried to help a friend out with his new laptop. It is a Toshiba Satellite L30 that came with Vista Home Basic pre-installed. After he plugged in a USB hard disk and installed Windows XP on the external, his laptop rebooted with the “the file is possibly corrupt. the file header checksum does not match the computed checksum” error message. After rescuing data on his internal hard disk we restored the system from the toshiba restore disk and everything worked fine again. He then went out and bought 2 Gb of RAM. I inserted the memory for him and it booted up fine with 1 Gb plugged in. I then plugged in the second Gb and suddenly the “the file is possibly corrupt…” error reappeared. Could it have something to do with a hardware checksum?
October 10th, 2007 at 3:12 pm
It did not work for me. It still has it set at 3573MB. It kind of saddens me as i bought 4 X 1GB ram sticks and can only use 3.5 of them. I would upgrade to a 64bit, but i would rather be able to use my computer as a gaming comp.
Oh Bother.
CJS
October 14th, 2007 at 8:56 pm
There is a major misconception when it comes to Windows incorrectly reporting the amount of system memory on 4GB+ systems. Even though Windows reports less than the 4GB, PAE allows the system to still access all 4GB whether Windows shows the correct amount or not (more on that below).
However, there are many reasons why this ‘tweak’ is invalid…
1:] By default, PAE is automatically enabled by all NT OSes from Win2k and up as long as the processor natively supports PAE. In other words, if your processor does not support PAE, >4GB of RAM will not be accessible by the operating system and/or applications regardless of what tweaks you use. Only switching to a PAE enabled CPU or to a 64-bit OS will fix that.
2:] Seeing as how Win2k and up all enable PAE by default if the CPU supports it, this ‘tweak’ is null & void. There is no need to ‘turn it on’. Furthermore, forcing PAE on a non-PAE processor in the OS can cause an unnecessary increase in processor cycles and potential memory leaks.
3:] PAE is fine if you have multiple processes accessing >4GB of system memory, however, no single 32-bit process will be able to access all 4GB+ regardless of PAE. This is one reason why Windows still incorrectly reports the amount of system memory on 4GB+ systems even with PAE enabled.
This so-called tweak will likely follow in the footsteps of other ‘urban legend tweaks’ such as the never ending /prefetch:1 tweak (which was debunked by a member of Microsoft’s development team several years ago).
Sources:
Bachelors in IT & NSF
A+, Net+, Linux+, MCSE, MCAD, MCSD, & CCNA certified
Former software engineer for Sun Microsystems
October 14th, 2007 at 9:08 pm
A quick correction to the above…
“1:] By default, PAE is automatically enabled by all NT OSes from Win2k and up”
was supposed to have read…
“1:] By default, PAE is automatically enabled by all 32-bit desktop OSes from Win2k and up”
(It does have to be manually enabled in boot.ini on 32-bit Win2k Advanced Server, Server 2003, and I hear on 32-bit Server 2007 as well)
October 23rd, 2007 at 10:43 am
Update for Windows Vista (KB929777) has a patch download that allows for 8GB RAM in Vista
December 4th, 2007 at 4:13 pm
oh doode!
this finally opens me eyez.. to a point.. i didnt understand why vista shows 2 the user that theres only 3.2GB of RAM, even with PAE forced on?
” Windows still incorrectly reports the amount of system memory on 4GB+ systems even with PAE enabled.”
becouse windows is a single process or what?
December 12th, 2007 at 5:21 pm
latest update on this subject: before i had a 4gb and PAE enabled in vista and i never seen 4gb but just today i install the vista sp1 rc and i can see all the 4gb again my problem been solved alone with the sp1 and i have the vista 32 bit
December 15th, 2007 at 11:02 pm
Well it was very interesting to see all the replys concerning the 4 gig limitations. Here is my story. I have an intel 945gnt MOBO that according to intel has 4 gig mem capable. Ok I put my 4 1 gig sticks in and booted up Vista Ultimate 32 bit and saw something around 3 gig memory then started reading that I must have Vista Ultimate 64 to be able to see all 4 gigs memorybut that turned out to be false cause right now running the vista 64 bit typing this message and I have 3326 meg mem. So so much with the having 64 bit Vista on my system. Oh yeah I have a Nvidia 512 DDR2 video card and have a fax modem too. Now if I remove the vid card anmd use on board video chip and remove the modem I still do not get my system to say I have 4 gig. SOmething around 3.6 or so. So any more bright ideas? I have a legit copy of server 2003 that I am planing on using to see if it says I have 4 gig memory or not. I will save this link to my flash so I can get back to this place
December 15th, 2007 at 11:08 pm
This get better each time i try something new.
At the beginning I found this
“1) Access cmd: Click on the Start Pearl > type cmd in the Search Bar > and press Ctrl + Shift + Enter (this allows you to run cmd in administrative mode)
2) Type BCDEdit /set PAE forceenable
WELL guess what? This makes about the 3rd or 4th one I have tried without success. Oh here is the reply I got when i ran the above.
This was the opening with CMD
“Microsoft Windows [Version 6.0.6000]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.
C:\Users\Southern>BCDEdit /set PAE forceenable ( after I press ENTER I got the following line)
The boot configuration data store could not be opened.
Access is denied.
C:\Users\Southern>
January 22nd, 2008 at 12:23 am
Who should patching about this issue, microsoft or mobo vendor?
January 28th, 2008 at 3:29 pm
I’m not a very technical person when it comes to PC hardware so most of this post is over my head but I do have one question about the 4G RAM limitation.
My situation: I have a desktop running Vista Home Premium w/ 3G of RAM out of the box. I got hooked on World of Warcraft on-line game so I wanted to ‘buff’ my PC up a little since I bought an extra LCD that I was unable to use b/c of the lack of an extra place to connect. Today I bought a Nvidia (spelling?) 8600 512RAM video card and a 1G memory upgrade and had Geek Squad install both.
So my question is: Will the 1G extra, bringing my PC up to 4G, actually make my PC run slower than if I would have left it alone? I don’t mind if it doesn’t get the ‘maximum’ use out of the extra gig - it was on a really good sale - so even if it added just a little extra RAM I’m completely ok w/ that, but from what I’m hearing did installing the 1G actually slow down my PC?
I want to thank anyone in advance for answering this - I’m a little lost and would really appreciate just putting my mind at ease that I didn’t muck anything up.
February 3rd, 2008 at 8:34 am
Is it possible to convert about 1GB or 0.5GB of a 32bit-4GB system’s unaddressable space to a RAMDisk like configuration that addresses the additional memory and allows for things like prefetch, readyboost, browser cache etc. to load up an image during boot-up PnP hardware scanning? Is it impossible to design something like this, given BIOS design or kernel design constraints. Ideally I would love a simple BIOS flag that hides a small amount of memory from the OS and reports it as a Hard Disk. Software and OS designers can write Prefetch like routines to speed the system.
February 6th, 2008 at 3:50 pm
southern gent, you need to disable users account security in vista.
February 8th, 2008 at 7:18 pm
Scribe13:
More RAM will never slow your PC down unless you’re overclocking, but we won’t go into that.
However, I’m pretty sure you don’t need 4Gig Ram. What you should aim for is a better CPU or Video Card. Although an 8600 is good enough for WoW.
February 8th, 2008 at 8:46 pm
albert:
Thanks for the info - it’s a relief to know I didn’t slow it down. I didn’t think 4gig Ram was needed but since I had a good deal on memory and a geek squad who owed me a free install I thought why not.
Since upgrading my video card I have noticed a remarkable improvement playing WoW.
Thanks again for helping me put my mind at ease!
March 4th, 2008 at 5:46 am
hello guys i am also facing a similar problem
i am using an hp work station pc which i brought only for designing purpose,
it has an 8 gb of ram
and this PC came along with a 64bit vista OEM
(i also have an XP SP2 32 an d 64 bit licence)
i and i use a software that is in local language
name of the product is ISM PUBLISHER which works only in 32 bit
i cant simply install this product coz it comes with a hardware lock. this thing worked fine on a 32 bit vista pc and xp pc
now PLZ give me a solution for
1, i dont want to degrade to 32 bit vista which will affect the total performance of my WORKSTATION
2, or if downgarding is the only option give me a pure solution to utilise that 8 gb ram
March 9th, 2008 at 12:47 am
aNiSh:
You can try Virtual PC to run your 32-bit apps. A 32-bit version of Vista will not be able to utilise more than 4GB of RAM.
Here is the link to my Virtual PC article:
http://vistarewired.com/2007/02/21/virtual-pc-2007
March 12th, 2008 at 1:35 am
[...] How to Enable More Than 3.5 GB of Memory in 32-Bit Windows Vista [...]
March 13th, 2008 at 5:47 pm
32 bit = 2^32 = 4,294,967,296 ~ 4GB. This is max addressing on 32 bit system. 1GB of other devices (i.e. video, etc.) drops memory mapping from 4GB to 3GB. The memory is physically there, but the mapping is taken up by other devices, so this RAM can’t be accessed. The less driver memory you have, the closer RAM availability will get to 4GB. I wish I would have thought of this before I bought 2 - 2GB cards, but I guess even 100MB gain could be better than none.
April 18th, 2008 at 2:58 am
Guys… according to microsoft, all variants of XP 32bits(I suppose vista as well!) and even Server 2003 32bit Std Edition is restricted to 4GB of ADDRESSABLE memory space. Which is why turning on PAE has no effect for some of you guys.
http://msdn2.microsoft.com/en-us/library/ms791485.aspx
April 18th, 2008 at 3:13 am
For those of you who have Vista SP1, and it reports 4GB, don’t be too happy yet. Vista is only reporting the RAM installed. Not the Ram usable by windows.
http://support.microsoft.com/kb/946003/
April 29th, 2008 at 11:04 am
Also, PAE is used like the old /3GB switch was used. It is for a sinlge process to be able to use up to 3GB of memory, rather than 2GB…. it has nothing to do with how much RAM the system uses or recognizes.
April 30th, 2008 at 12:57 am
I Have an important question…i can’t find anyware the real answer - i have been googling for days.
I have a windows server 2003, 32 bit.
i have a IBM XSeries 365 or x3850 , (ibm 3u server)
I have 4Gb ( and i can add up to 16 GB of RAM to the IBM SERVER)
when i have 4 GB - my windows only sees up to 2.5 GB.
this is because of something called PCI HOLE , where my pci cards takes up all the addresses below 4GB.
so i understand why this is happening, but ok, what can i do about it??
i put on the /PAE flag in the boot.ini file. and than i can see all my memory 4GB or even 16 GB in the windows(32 bit i remind you).
But the problem is that my pci card doesnt work now!
i think it is becaue i took out the pci hole..so the pci cards doesnt have the (MMIO) address space it is needed.
I digg up some more, and i read about something called remapping the address space of the PCI, tell him to take didffrent address space…
it is suppose to be somewhere in the BIOS Settings, i couldnt find it in my bios I HAVE the newest version available for my IBM X Series server.
can someone tell me if it is really possible to do what i want to do? and if so? how can i do it….
i don’t understant why my server can have like 6 PCI cards and alotttt of RAM Slots if it can’t use them all together…and the windows 2003,32 bit is not the problem - because the /PAE flag is fine for it….and it can see all the memroy and pci cards i install,
it doenst make sense that /PAE doenst work with PCI CARDS well…what kind of a patch/option is it than?
May 11th, 2008 at 11:39 am
Hi all I have been reading all of your comments and I don’t know why but I have Vista 32 bit installed and I was going to change over to 64 bit untill i relized i would loose all of my info because you cant upgrade to 64 but that is beside the point he is what i have to tell you I was putting 64 on another harddrive in my same comupter running 32 ( i wanted to compare the speeds side by side) But after I removed the harddrive with the 64 and rebooted my computer it was showning all 8 gigs of memory where before it was only showing 3 the computer has been rebooted many times since and as of today it is still showing 8 and if you go into the thask manager and look it shows all 8 there so is it really using it or not.
May 20th, 2008 at 9:14 pm
Great Article and wonderful information. But still no solid answer to fix the problem. I installed 2G memory on my Sony Laptop which came with 2G and I run into the same problem. The BSDEdit command did not help.
June 4th, 2008 at 9:21 pm
c:\users\amdministrator>BCDEdit /set PAE forceenable
c:\users\amdministrator>
This Command Completed Succesfully
As I was just curious to see how this would turn out, it did work though I am using Two 8600GT SLI mode Video cards a notice out of 4Gb I was knocked down to 2.25Gb after just giving this a shot I notice It kicked back up to 2.75Gb of Random Access Memory. Though this was done on a Biostar Motherboard
Now About that i am hearing of Vista x64 spoke of in hear, As i did waste some money on that DVD, To me Vista x64 seemed to be more antsy, really didnt like the fact that most of my programs couldnt be installed, even though their was a (x86) folder in Program Files,
The RAM was a issue at first pretty much I could on install (x64)Vista with a max of 2Gb other it would crash during installation (A Stop Error) But after the Hot Fix I believe it was KB929777 or close I was then able to insert the rest of the Mem Mods back in giving a total of 4Gb Also Being all recognized. Even In (x64)Vista 4Gb of RAM is Still Plenty <as this is my own opinion.
June 4th, 2008 at 9:23 pm
Edit To Above: Sorry about the Double Post:
Correction of Mispellings:
c:\users\administrator>BCDEdit /set PAE forceenable
c:\users\administrator>
This Command Completed Succesfully
June 6th, 2008 at 2:31 pm
i have dell inspiron 1525 with vista premium and desktop pc with vista ultimate
after installing sp1 both the system recognizes a complete 4 GB ram .before it recgnized only 3.5GB
they are both 32 bit
June 19th, 2008 at 9:02 pm
shouvik
Yes once Vista SP1 is installed your system will recognize the 4Gb of RAM. One thing that Microsoft did manage to fix. As I said One thing, though their are many fixes to come, heres the catch… Unless you are using any programs that require any large amount of memory, vista will still not utilize all 4Gb Of RAM. Though Just by updating my score. I went up from 5.9 base score to 6.0 base now much of a Increase, but some,
Vista Is still in its early years, I believe that atleast within another year we should should see a fairly good OS and even better within 2 to 3 years, As I will be patient with this OS I myself Am very curious to as how good this OS will be in the near future.
July 9th, 2008 at 1:56 pm
Hey…
My system shows me that I have 4gigs of ram (the Vista systems tab). I run Vista 32 bits….how come it can still detect it? Can it see it but not use the RAM?
July 13th, 2008 at 6:37 pm
So if i do /bcdedit set increaseuserva 3072 and have 4g of ram will that leave enough ram for the kernel (1gb) even though i have two 8800gt (512mb). I am using vista32 btw.
July 13th, 2008 at 6:39 pm
Edit to above
I currently have it set to /bcdedit set increaseuserva 2560 as wasnt sure.
July 17th, 2008 at 5:32 pm
Worked on Asus P5B w/4Gb, Intel Processor and Vista Business