Author Topic: Access more memory, even on a 32-bit system (Read 42658 times)

Broni · « **on:** December 19, 2008, 04:48:01 PM »

Quote

No matter how much memory you have in your PC, you may not be getting the most out of your installed RAM.

A few little-known system tweaks can improve the way Windows manages memory, freeing up more RAM for your applications.

As described in an entry on the Microsoft Developer Network, all non-server 32-bit versions of Windows XP and Vista impose a memory limit of 4GB. Your system may allow you to install more than this amount of RAM, but with few exceptions, the extra memory won't do Windows or your applications any good.

Moreover, even if you have 4GB of memory installed in your PC, you may not be able to use it all. For example, if your video card comes with 1MB of memory and you have 4GB of RAM, your system actually has 5GB of memory physically installed. But Windows will use only 4GB of that total, regardless.

It gets worse: according to a comment posted to the MSDN article, Windows itself is getting only 3GB because the video card gets 1GB. This happens because the memory aperture — a portion of system memory — is used to work with the video system.

Ways to break through Windows' RAM ceiling

Fortunately, there are techniques you can use to get around Windows' system-memory limitations. One method is to use Physical Address Extension (PAE), a feature of x86 processors that lets 32-bit operating systems overcome the 4GB memory limit.

Another MSDN article explains that 32-bit Windows operating systems support PAE. Even though XP and Vista still cling to the 4GB limit with PAE enabled, the feature may help you get back some of your unused RAM.

In one or two rare cases, a developer may take advantage of PAE technology to get around the usual Windows limits. For example, reader Alan Gorski reports that when he increased a computer to 8GB, the program AutoCAD was able to open large drawing files without generating the "out of memory" errors he previously had seen. As Gorski notes, "AutoCAD has long used special memory management techniques since the DOS days to maximize use of available RAM."

There's a good chance your system is already using PAE. That's because Windows relies on the technology to support the security feature known as Data Execution Prevention (DEP). For more information about Windows and DEP, see my Top Story in the May 3, 2007, issue.

If a computer supports hardware-enforced DEP, then PAE is enabled as well. Here's how to check for it in Windows XP:

* Step 1. Choose Start, Run.
* Step 2. Type sysdm.cpl and press Enter.
* Step 3. Click the Advanced tab. In the Performance box, click Settings and choose the Data Execution Prevention tab.
* Step 4. Look for a status message at the bottom of the dialog box. If it indicates that your hardware does not support DEP, chances are PAE is not enabled.

To check your system's PAE status in Vista, do the following:

* Step 1. Press Win+R to open the Run dialog box.
* Step 2. Type SystemPropertiesDataExecutionPrevention and press Enter.
* Step 3. If prompted by User Account Control, click Continue.
* Step 4. If the status message at the bottom of the dialog box says your system supports DEP and the "Turn on" button is selected, then PAE is enabled as well.

If PAE is not already enabled on your system, here's how to activate it in Windows XP:

* Step 1. Choose Start, Run.
* Step 2. Type notepad c:\boot.ini and press Enter.
* Step 3. Under the [operating systems] heading, look for a line that contains the /noexecute switch, which turns software DEP. For example, it may be /noexecute=optin, /noexecute=optout, or /noexecute=always on. Place the cursor directly after that switch and type a space followed by /pae. Save the file and reboot.

If you don't have DEP enabled on Vista (or you don't want it enabled), you can still activate PAE by following these steps:

* Step 1. Click Start, type cmd.exe and press Ctrl+Shift+Enter.
* Step 2. If prompted by User Account Control, click Continue. This opens a command prompt window with administrator privileges.
* Step 3. At the prompt, type BCDEdit /set PAE ForceEnable and press Enter.

You can read more about PAE in this post on Microsoft's TechNet site.

Microsoft warns in another TechNet article that some drivers will not load if PAE is enabled. After you make this change, keep an eye on your system. If you have problems with drivers or your system starts acting up, remove the /pae switch from boot.ini in XP, or enter the following command line in an administrator command prompt in Vista:

BCDEdit /set PAE ForceDisable

Now, my comment...
I have DEP disabled (my choice), so I decided to use BCDEdit /set PAE ForceEnable command to enable PAE.
I restarted computer, and opened same 5 applications, I had opened before applying the above command:
Firefox, Thunderbird, Windows Explorer, Wordpad, and uTorrent.
These are Task Manager readings, regarding RAM ("Performance" tab):
BEFORE - total-2045; cached-1193; free-37; memory usage-55%
AFTER - total-2045; cached- 1540; free-5; memory usage-39%
As you can see, "cached" part of RAM (which is the most important part; it's your "working" RAM), increased by almost 350MB, knocking "memory usage" down by 16%.

I hope, my conclusion is correct, and I still have to use the computer for a while to see the real effect.

I'm also very curious about the results from someone, who has 3, or 4GB of RAM installed on 32-bit system.
I have 2GB.

patio · « **Reply #1 on:** December 19, 2008, 07:10:40 PM »

Very nice review on this...
So because you're attempts at sabotaging my Vista install have fallen by the wayside you tempt me to do this on my benchtest machine with XP just to see the inevitable results .....
You have tweaked my interest...Onward i say ! !

Broni · « **Reply #2 on:** December 19, 2008, 07:14:11 PM »

I won't rest until I screw one of your machines....that's my motto.....LOOOOOOOOOOOOOOOL

Broni · « **Reply #3 on:** December 19, 2008, 07:17:54 PM »

Joking aside, I'm basically waiting for my Firefox to reach 300-400MB of RAM usage.
Normally, at that point, FF becomes very slow, and I have to restart it.
Right now, FF is at 228MB.

Carbon Dudeoxide · « **Reply #4 on:** December 20, 2008, 04:26:29 AM »

Broni. Seen this?
http://www.computerhope.com/forum/index.php/topic,33321.0.html

Ever since that Config edit, all Firefox needs is a good minimize.

Calum · « **Reply #5 on:** December 20, 2008, 05:20:18 AM »

PAE is enabled by default on most systems anyway, to enable DEP.
I know on regular XP, using PAE does not enable more than 4GB of memory, no matter what. Server 2003, however, could see all my 4GB of memory when I enabled this.
There's an interesting article on this somewhere, which points out that PAE is not the magic solution to break the 32 bit barrier, but I can't remember where it was.

Broni · « **Reply #6 on:** December 20, 2008, 05:41:47 PM »

Carbon
Minimizing FF doesn't work for me at all. Memory usage goes down just by a few MB.

Quote

I know on regular XP, using PAE does not enable more than 4GB of memory, no matter what. Server 2003, however, could see all my 4GB of memory when I enabled this.

I understand, that there is no way to break 4GB barrier, but I'm just curious about being able to use more RAM inside 4GB. Like you said, you can see change with Server 2003.
PAE may be enabled by default, but I disabled DEP by choice, and when I checked on PAE, it was disabled as well.

Calum · « **Reply #7 on:** December 21, 2008, 04:06:50 AM »

Oh, I get you now.
What I mean is, on XP with my system, system properties reports 3.2GB of RAM. With Server 2003, it reports 4GB. That breaks the 4GB barrier by using 36-bit access - it sees 4Gb of RAM, plus 512Mb video RAM, plus the other memory allocated to devices.

Broni · « **Reply #8 on:** December 21, 2008, 11:45:32 AM »

That's interesting. Why do you think, it happens with Server 2003, but not XP?

Calum · « **Reply #9 on:** December 21, 2008, 12:28:19 PM »

http://www.computerhope.com/forum/index.php/topic,72489.msg473066.html#msg473066
killberb explains it there.
Apparently some drivers can have trouble with over 4GB of RAM available, so "home" 32 bit OSes cannot access more than 4Gb of RAM, period, because it's disabled.
Server OSes can use the extra 4 bits provided by PAE to access more memory.

Broni · « **Reply #10 on:** December 21, 2008, 01:54:37 PM »

I see...thanks.

macdad- · « **Reply #11 on:** December 26, 2008, 07:42:46 AM »

does this work for all 32Bit versions of Windows(like NT and 2000) or is it just for XP and Vista?

BC_Programmer · « **Reply #12 on:** December 26, 2008, 08:44:58 AM »

I don't think PAE support was available until XP was released.

Broni · « **Reply #13 on:** December 26, 2008, 12:04:10 PM »

According to M$, it's supported since 2000/NT: http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx, however the processor has to be Intel Pentium Pro and later.

BC_Programmer · « **Reply #14 on:** December 26, 2008, 12:05:39 PM »

Alright- thanks Broni.... NT4 supported PAE?

Broni · « **Reply #15 on:** December 26, 2008, 12:50:49 PM »

According to this: HERE, yes.

macdad- · « **Reply #16 on:** December 27, 2008, 08:33:10 AM »

Thanks Broni, but crap i cant upgrade my memory past 512MB, from what Crucial says of my system(here).

but oh well... my rig probably wont need more than 512MB RAM anyways, Win 2K RAM requirement(64MB) - 384MB = 320MB plenty of space

patio · « **Reply #17 on:** December 27, 2008, 09:04:48 AM »

Win2K runs nicely on 512...sweeter on 768 but you should have no issues.

macdad- · « **Reply #18 on:** December 29, 2008, 01:05:29 PM »

*Adding another 128MB*

thanks for the tip Patio

patio · « **Reply #19 on:** December 29, 2008, 04:04:00 PM »

Win2K IMHO is the stablest OS Microsoft ever released...
I need to re-boot that machine about every 3 weeks ...other than that it runs 24/7.

macdad- · « **Reply #20 on:** December 30, 2008, 06:00:20 AM »

thats good, you probably added another fan or even watercooling if it runs everyday.

michaewlewis · « **Reply #21 on:** December 31, 2008, 03:15:51 PM »

If you need more memory and require a 32 bit os, just switch to ms server 2003 enterprise edition. It supports up to 64gb on x86.

http://technet.microsoft.com/en-us/windowsserver/bb430827.aspx

Otherwise, just use 64bit.

macdad- · « **Reply #22 on:** December 31, 2008, 03:34:38 PM »

i dont think you would need 64GB of ram for personal use, so you could just probably get XP, and do the mod that Patio posted for upgrading the max amount of memory.

michaewlewis · « **Reply #23 on:** December 31, 2008, 03:35:48 PM »

I'm just saying ya could....... $:-\$

BC_Programmer · « **Reply #24 on:** December 31, 2008, 03:37:08 PM »

Quote from: michaewlewis on December 31, 2008, 03:15:51 PM

If you need more memory and require a 32 bit os, just switch to ms server 2003 enterprise edition. It supports up to 64gb on x86.
http://technet.microsoft.com/en-us/windowsserver/bb430827.aspx

Otherwise, just use 64bit.

we're forgetting something though.

how do programs access memory? Pointers. what size are pointers? 32 bits.

A program would need to be specially constructed to use more then 4GB of memory if it is written for a 32-bit OS. (special API constructs aside)

michaewlewis · « **Reply #25 on:** December 31, 2008, 03:44:13 PM »

What programs ever need 4gb of memory for itself? The only programs I've seen that use anywhere near 4gb of memory are sql servers and sql server 2005 can handle as much memory as the os can throw at it..... If any other program is using that much memory, it was probably written specifically to crash the os.

BC_Programmer · « **Reply #26 on:** December 31, 2008, 03:48:49 PM »

Some pointers are absolute, and don't point to memory locations in the process address space. Mostly drivers, which could easily be constructed to prevent problems.

macdad- · « **Reply #27 on:** December 31, 2008, 04:12:52 PM »

but micheal, that is a good tip though

BC_Programmer · « **Reply #28 on:** December 31, 2008, 05:22:14 PM »

that's true, I know if I ever need to reformat my machine, I'm going to put 2003 on it.

Calum · « **Reply #29 on:** January 01, 2009, 10:09:44 AM »

Server 2003 is a great OS, my second favourite after XP X64.
Expensive, though.

BC_Programmer · « **Reply #30 on:** January 01, 2009, 10:36:06 AM »

Quote from: Calum on January 01, 2009, 10:09:44 AM

Server 2003 is a great OS, my second favourite after XP X64.
Expensive, though.

I was smart though, I got it will I was at school and was able to get it through that academic discount they had- I recall at the time XP pro was 12 dollars after the discount...

macdad- · « **Reply #31 on:** January 01, 2009, 01:49:22 PM »

but lets just say that if you get Windows ME, then your instantly screwed. its probably the least stable OS ever..

but yea 2003 is great and very powerful OS but its probably for more advanced users, since it was designed as a Server OS, and not a personal OS. Windows 2K, XP Pro and XP 64 are my favs.

patio · « **Reply #32 on:** January 01, 2009, 01:51:15 PM »

Win2K rules...

macdad- · « **Reply #33 on:** January 01, 2009, 01:58:42 PM »

Quote from: patio on January 01, 2009, 01:51:15 PM

Win2K rules...

such a great OS. an even better when you get to the Admin Tools

but it stinks that it doesnt include Windows Movie Maker, but of course its a buisness oriented OS. as seen here

patio · « **Reply #34 on:** January 01, 2009, 06:38:57 PM »

WMM will run on Win2K...

macdad- · « **Reply #35 on:** January 02, 2009, 08:09:46 AM »

it wont i've tried the XP version and it said "Can only be installed on Windows XP"
and the ME version isnt available for download unless you own Windows ME.

Broni · « **Reply #36 on:** January 02, 2009, 10:21:37 AM »

Just did some digging...
Try AutoPatcher 2000: http://www.softpedia.com/get/System/OS-Enhancements/AutoPatcher.shtml
It includes Windows Movie Maker 1.2

michaewlewis · « **Reply #37 on:** January 02, 2009, 11:01:23 AM »

When you upgrade to 2003, make sure you get the enterprise edition, not the standard edition.....

Costs twice as much as standard (around $1800), but allows you more memory.

computeruler · « **Reply #38 on:** January 02, 2009, 11:27:02 AM »

woa so scence i have 2gb ram and a 1gb gpu im only getting 1gb or ram and 1gb vram!? this is an outrage!
so for xp to turn it on it should look like this right /NoExecute=OptIn /pae

Calum · « **Reply #39 on:** January 02, 2009, 11:43:45 AM »

computeruler - you're getting 2GB of RAM and 1GB of VRAM.
The cap is 4GB, so you won't see more than just under 3GB of RAM.
Did you read anything of the discussion above, by the way?
PAE doesn't work like that in XP.

Broni · « **Reply #40 on:** January 02, 2009, 11:46:16 AM »

Quote

Did you read anything of the discussion above, by the way?

He's been busy, working on his spelling....

computeruler · « **Reply #41 on:** January 02, 2009, 11:47:43 AM »

ok then ya ive been busy with my spelling

patio · « **Reply #42 on:** January 02, 2009, 11:53:27 AM »

And sorting out his alter ego status...

macdad- · « **Reply #43 on:** January 02, 2009, 12:02:53 PM »

thanks Broni for the link, i downloaded and installed AP.

macdad- · « **Reply #44 on:** January 02, 2009, 12:10:33 PM »

and suprisingly its much-much faster on startup and added a whole lota apps to my rig!

Thanks!

Broni · « **Reply #45 on:** January 02, 2009, 12:41:04 PM »

If so, I'm gonna do it on my 2000, as well....

macdad- · « **Reply #46 on:** January 02, 2009, 12:42:55 PM »

well it may vary. but i dont know maybe u'll have better luck. since i did have some missing updates when i installed AP.

BC_Programmer · « **Reply #47 on:** January 02, 2009, 01:17:11 PM »

Quote from: Broni on January 02, 2009, 12:41:04 PM

If so, I'm gonna do it on my 2000, as well....

ahh, CH users are your guinea pigs.

I approve.

Broni · « **Reply #48 on:** January 02, 2009, 01:18:40 PM »

Shhhhhh....

BC_Programmer · « **Reply #49 on:** January 02, 2009, 01:24:54 PM »

Quote from: Broni on January 02, 2009, 01:18:40 PM

Shhhhhh....

I mean, you LET them test bleeding edge software. It's not so you don't get cut, but rather because you care so much about their software well-being that you want them to use the latest and greatest. Even if it is a double-edged sword. I mean, even if the butter is on the other side of the knife...

Broni · « **Reply #50 on:** January 02, 2009, 01:30:02 PM »

I'm not THAT bad. I test stuff too

macdad- · « **Reply #51 on:** January 02, 2009, 01:30:48 PM »

oh well(look at pic)

the next recommendation for your proccessor, it could just turn into(look at 2nd pic)

and of course its all joke

[attachment deleted by admin]

Broni · « **Reply #52 on:** January 02, 2009, 01:37:54 PM »

I just installed AP. All well

macdad- · « **Reply #53 on:** January 02, 2009, 04:28:47 PM »

Quote from: BC_Programmer on January 02, 2009, 01:24:54 PM

Quote from: Broni on January 02, 2009, 01:18:40 PM
Shhhhhh....

I mean, you LET them test bleeding edge software. It's not so you don't get cut, but rather because you care so much about their software well-being that you want them to use the latest and greatest. Even if it is a double-edged sword. I mean, even if the butter is on the other side of the knife...

if that did happen, then my guinea pig WOULD come after you

BC_Programmer · « **Reply #54 on:** January 03, 2009, 09:22:11 AM »

Quote from: macdad- on January 02, 2009, 04:28:47 PM

Quote from: BC_Programmer on January 02, 2009, 01:24:54 PM
Quote from: Broni on January 02, 2009, 01:18:40 PM
Shhhhhh....

I mean, you LET them test bleeding edge software. It's not so you don't get cut, but rather because you care so much about their software well-being that you want them to use the latest and greatest. Even if it is a double-edged sword. I mean, even if the butter is on the other side of the knife...

if that did happen, then my guinea pig WOULD come after you

Why? does your guinea pig like butter?

macdad- · « **Reply #55 on:** January 03, 2009, 11:40:12 AM »

i dont own a guinea pig....but....
nvm

patio · « **Reply #56 on:** January 03, 2009, 12:42:07 PM »

Then who's that furry critter in the photo ? ?
Are you not telling us everything ? ?

BC_Programmer · « **Reply #57 on:** January 03, 2009, 12:43:16 PM »

ahh, I see, you don't "own" the guinea pig, your his friend, with benefits.

This may explain his familiarity with butter.

macdad- · « **Reply #58 on:** January 03, 2009, 03:40:12 PM »

mmm....Butter Toast

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Author Topic: Access more memory, even on a 32-bit system (Read 42658 times)

Broni

patio

Broni

Broni

Carbon Dudeoxide

Calum

Broni

Calum

Broni

Calum

Broni

macdad-

BC_Programmer

Broni

BC_Programmer

Broni

macdad-

patio

macdad-

patio

macdad-

michaewlewis

macdad-

michaewlewis

BC_Programmer

michaewlewis

BC_Programmer

macdad-

BC_Programmer

Calum

BC_Programmer

macdad-

patio

macdad-

patio

macdad-

Broni

michaewlewis

computeruler

Calum

Broni

computeruler

patio

macdad-

macdad-

Broni

macdad-

BC_Programmer

Broni

BC_Programmer

Broni

macdad-

Broni

macdad-

BC_Programmer

macdad-

patio

BC_Programmer

macdad-