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Upgraded my laptop RAM to 4GB but it only detects 3GB.. Help

by LoneRiderz / December 11, 2007 9:06 PM PST

Went to Sim Lim Square to upgrade my laptop memory, it was running on 1GB, really slow as preloaded with Vista. Bought 4GB (2sticks of 2GB, DDR2 667) of Corsair, as the vendor says its the one most compatible with most motherboards. Went to another shop which installed it for me(since my hands experience tremors and I was hoping a techie would be more proficient at it). Problem is windows only detects 3GB though my laptop spects (Acer Travelmate 6292 2.0GHz). He can't resolce the problem.. Anyone can help?

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That's proper.
by R. Proffitt Forum moderator / December 11, 2007 10:00 PM PST

Very well documented, discussed and why you read my posts to stop at 2GB today.

Here's just one of thousands of links on the issue ->

No, there is no fix for 32-bit Windows as this is exactly how it should work.

No, I do not suggest you try a 64-bit Windows as there are severe issues for most owners in regards to drivers, choice of antivirus and other support issues.

Yes, the /3GB switch might help some applications but it turns out only a few will benefit.


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Thanks but..
by LoneRiderz / December 12, 2007 12:13 AM PST
In reply to: That's proper.

The specs on the laptop says max of 4GB RAM.. Is there anyway to make windows access the other 1GB of RAM? Or am I stuck with 3GB of usable RAM wasting 1GB?

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I answered that. But...
by R. Proffitt Forum moderator / December 12, 2007 12:34 AM PST
In reply to: Thanks but..

I strongly suggest that you don't move to a 64-bit version of Windows.

Nothing is broken here so there is nothing to fix. That may take some longer to accept. At least there is plenty of articles on this one.


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And to make sure you know this...
by R. Proffitt Forum moderator / December 12, 2007 12:35 AM PST
In reply to: Thanks but..

Even if you were able to get 32 bit Windows to note all 4GB, Windows LIMITS APPLICATIONS TO 2GB. Documented behavior, well discussed.


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The Specs are accurate. It means you physically
by orlbuckeye / December 12, 2007 7:56 PM PST

can put 4 gigs on ram in the machine. You need a 64 bit OS to use all 4 gig. Someday we will be able to access 128 gig with a 64 bit OS. That kind of memory isn't affordable for the common consumer.

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Upgraded my laptop RAM to 4GB but it only detects 3GB.. Help
by zytham18 / December 14, 2007 12:29 PM PST

Dear R. Proffitt,

I personally think that it is cause by his laptop's motherboard. The laptop's motherboard of his cannot support until 4 GB.

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What will it take to change your thinking?
by R. Proffitt Forum moderator / December 15, 2007 1:09 AM PST

Now we have two problems to solve.

1. You think it's not right.

2. The 32 bit versions of Windows do report less than 4.0GB.

Hang in there, I'm sure someone can explain it in the words you'll accept. Please do not part with money trying to fix this. It's not something money will fix. Only by discussion and a little more education will it all become clear.


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Thanks for all the help guys..
by LoneRiderz / December 15, 2007 1:50 AM PST

Seems that Acer's motherboard does support up to 4GB as told by their customer service and as I can see it on their motherboard control software (Acer eSettings Management) which reports the true amount of RAM. They also inform me that the 3GB is due to Vista 32bit.. No surprise there. I'm gonna leave the extra memory in there in case I move up to a 64bit OS or get another laptop..

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There you go!
by Swartswaan / December 15, 2007 2:31 AM PST

Good luck!! You got it!

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4GB Max for Laptop - Yes! 3GB Max for Windows - Yes!
by Zeppo / December 15, 2007 3:30 AM PST
In reply to: Thanks but..

I have 4GB of RAM in my desktop and wondered the same thing some time ago. All 4GB is used but only 3GB by 32-bit Windows. The rest is used by hardware, but for a technical explanation about that you should read the links other have provided you.

If you literally want to use all 4GB for Windows, you would have to go to a 64-bit version. But as others have noted, you will suffer a lot of problems with getting drivers for your hardware devices. And if you can't get a driver for a device, you have to replace the device with one there is a 64-bit driver for - there is no work-a-round!

The best time, in my view, for the masses to switch to a 64-bit version of Windows is when vendors, such as Dell, HP, SONY, Toshiba, Gateway, etc., start building them for consumers. Still, buyers would have to make sure all there external devices (printers, scanners, cameras, etc) have 64-bit drivers or replace them with ones that do.

Personally, I would love to go to a 64-bit system but just don't want to deal with the hassles of doing such.

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Vista 4GB Ram
by The Digital Guy / December 14, 2007 11:16 AM PST

I have had 4GB of Ram in my Vista Ultimate machine since I built it back in May. And it only reconizes 3GB of ram due to the 32 Bit Vista OS. However I downloaded today Vista SP1 RC and once installed it now shows 4 GB of Ram.
Here are the links for Vista SP1 RC. Please read carefully as on link is to enable Windows Update to download SP1 RC and the other link is to download the Full SP1 RC download. Again; PLEASE read carefully:

Full Download:

Hope this helps!!!

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Vista SP1 Doesn't Solve the Problem
by jhE6600 / December 14, 2007 2:26 PM PST
In reply to: Vista 4GB Ram

If you read Microsoft's release notes for SP1 RC1 carefully, you'll notice that they mention the 4GB issue: "With SP1, Windows Vista will report the amount of system memory installed rather than report the amount of system memory available to the OS." (

What this means is that in the past, Vista reported the amount of RAM that it was able to use, which was around 3GB no matter how much more you actually have. Now, however, with SP1 it reports the amount of RAM that is installed. So the bottom line is, Vista knows there is 4GB of RAM in there, but still can't access all 4GB because of the intrinsic limitations of 32-bit operating systems.

If the previous posters had not made this clear enough, the problem here is that 32-bit operating systems are limited to acessing around 3GB of RAM maximum because they do not have enough memory addresses to use 4GB of RAM since memory addresses are taken up by things like IRQs, drivers, etc. No matter what 32-bit operating system you install and no matter what hardware you have, you will only be able to use 3GB of RAM.

The only way to get past this is to install a 64-bit operating system, as previous posters have mentioned. However, they also correctly point out that you are likely to have many headaches with the 64-bit version of Vista since many drivers and software are completely incompatible with 64-bit Vista. If you insist on going 64-bit, Linux is a much better choice since the open source community has had excellent 64-bit support for a very long time, though in that case you will run into the incompatibilities that Linux presents as compared to Windows (many Linux distros cannot install on new motherboards because the kernel version they use is outdated).

So, a short summary: There is no way to get all 4GB of RAM to be actually accessible by any 32-bit operating system. However, you should not upgrade to a 64-bit operating system because you'll get a lot of grief from incompatible software and drivers. Vista SP1 reports 4GB of RAM because the way they display the amount of RAM installed has changed, but can still only use 3GB of RAM tops.

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32-bit systems can handle 4GB addresses
by Swartswaan / December 15, 2007 1:06 AM PST

Technically 32-bit systems can very well handle 4GB RAM. If you remember primary school sums, it went like this. Right-most column counts ones (1-9), next to the left counts tens, then hundreds and so on. (Ten to the power 0, 1, 2 etc.). Counting in two's (computers can only count in two's because electronic states are nominally on or off) it will look like this from right to left; 8 4 2 1. and also like this; 0000, 0001, 0010, 0011, 0110, 0111, 1000, 1+1=2 which causes the carry. With four bits like here you can only count to fifteen decimal: 8+4+2+1=15. When you get to the 32nd place (32-bit) you will be able to count to 4,294,967,295 bits. This will leave 294,967,295 addresses since 4GB is 4,000,000,000,000 bits.

The reason why your system is limited to 3GB most likely comes from an operational decision since not even Microsoft can change the physical realities of the machines they support. The program and data file sizes you see on your screen is not the reality. It is so much common cause that more space is used than shown that the discussion was dropped years ago. The machines we use today is rigged so that that issue surfaces as little as possible.

It is also assumed that your run a computer under the maxim of caveat emptor. It's a good idea to find out as much as possible on the machine you use before doing things to it. Even Bill is sometimes stuck for an answer. Be fair.

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Correction on 4GB.
by Swartswaan / December 15, 2007 1:10 AM PST

Sorry, 4GB is 4 with nine zero's, not twelve. Didn't pick it up on the preview.

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Close. BITS versus BYTES.
by R. Proffitt Forum moderator / December 15, 2007 1:36 AM PST
In reply to: Correction on 4GB.

4GB RAM = 4,294,967,296 Bytes or...
4GB RAM = 34,358,738,368 Bits.

Not that it matters here. The issue is how to convey the Windows 32-bit limitations to the new owner.


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There's a catch
by jhE6600 / December 15, 2007 1:32 AM PST

Yes, true, the way to calculate the amount of memory a 32-bit operating system can handle is by taking 2 to the power of 32. However, part of this 4GB of addressable space also includes addresses for things like IRQs (hardware interrupt requests), text-based graphics memory, device drivers, etc., as I said in part of my earlier response.
Almost all 32-bit operating systems do this, even in the presence of some limited workarounds (theoretically drivers can be addressed in memory space above the 4GB limit and so on, see, because very few firmware and drivers can support any other memory architecture. I've seen this happening in Linux, Mac OS (non-64-bit versions), and Windows.

So, I admit, I was not totally correct to say that 32-bit OSes are not allowed to address 4GB RAM, but practically speaking you'll be hard pressed to get support for addressing anywhere near the 4GB that's allowed, especially when sticking to Windows. In the end, you still need to wait for 64-bit to become mainstream to get larger amounts of RAM to be supported. Sorry if I misled anyone.

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4 gigs only showing 3
by rokitt51 / December 27, 2009 9:41 AM PST

Ive been reading the 32 bit and 64 bit deal here. I have an HP Pavillion that i installed 4 gigs of buffalo RAM in, before i resored the system, the system was reading all 4 gigs of RAM. Now it is only showing me that i have 3 gigs. Is there another explanation for this. I know that even with this 32 bit system, i can read all 4 gigs of RAM. That is how it was up until the restore. Reason for restore was system said that there was a hard drive failure, i couldnt use the laptop. Laptop is a DV9600 series.

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32 bit OS?
by R. Proffitt Forum moderator / December 27, 2009 10:34 PM PST
In reply to: 4 gigs only showing 3

Microsoft was slammed by the makers wanting a fix so MSFT issued some patch to have 32 bit Windows report but not use the added RAM.

This area is so well discussed that all I can say is the patch is just to placate the makers and users. It does nothing to utilize the RAM.

Hope this explains it for you.

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Not a real problem with 4 GB's and 3 detected
by marvinkirsh / December 14, 2007 11:29 AM PST

Hi: I had just bought an Acer Inspire 5920. Works fine but saw 2 GB DDR2 for notebook on sale at Office Depot at about 97 .00 bucks per 2GB chip. Remembering my experience with my desktop,chips and installed theminthe store boasting the RAM has a profound effect on performance-more than any other types of upgrades. So I purchased the chips and installed them in the store with a screw driver borrowed from the store. I was worried the same, as you described, when data in system in control pannel showed only three GB's available RAM. I was even more worried when the sales clerk said he thought something was wrong. I did notice however a much smoother and faster response time in applications. If one however looks further, despite the three GB's of available RAM, system specs in someother table I had lost rack of (in performance stats or ?) shows a full 4 GB's installed. Some RAM Iknow is shared with Graphics, or other applications, but this listing of 3 GB is basically irrelevant-and the machine will function a little smoother-especially when normally stressed with many processes running concurrently. The additional RAM is basically a good investment. I assume 3 GB is better than two maybe less than four (which the machine cannot use the same as two-i.e. as twice as much). If you look in system-hardware specs (or somehwere inyour machine)verses, operating specs --you will find the 4 GB all installed and operating satisfactorily. There is nothing wrong with your computer, the RAM installation or the RAM.

Marvin K.

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3GB Detected.
by Swartswaan / December 15, 2007 1:34 AM PST

Definitely a better answer than mine, but that was the line that I was thinking on. System management takes memory that is never discussed. The better response would be easily explained if you consider things like virtual memory and paging cycles. What do you see when you go into Device Manager? Maybe you will be able to increase your page file size to about 6GB (preferably 1.5x installed RAM max.) Mine is 5x RAM, no problem, but I have 140GB+ HDD spare.

Again, on the original query, get to know your computer better. You will never regret it. No need to fear it. Computers can be explained in English. After all Englishmen built them. Give me a more Brit surname than Gates. Yes, I also remember the Boston Tea Party.

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Vista Premium or Ultimate
by ourplace / December 14, 2007 1:08 PM PST

You can buy Vista Premium or Ultimate it uses 8gb otherwise, yes your stuck with only 3gb. (although I thought all Vista uses 4 or 8gb???)Also if you have Dual Channel memory DDR2 you should sell 2 of those sticks and buy 2X512mb sticks or else your XP won't even use the third 1gb stick, just the first matched 2 sticks = 2gb. BTW 2gb of fast memory (corsair) is plenty for any game out there. I just finished Crysis and I only have 2X1gb of corsair PC6400C4 Extreme 800mhz Dual Channel. Played on HIGH with a nVidia 8600 GT.

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ram problem
by alf / December 14, 2007 5:51 PM PST

That is the max that board will take, but if you have Vista it would not run any better with 10 gig Suggest you remove one chip and resell it.
And it will not change a thing.If you want it to run faster put in XP.

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That'll make it worse
by jhE6600 / December 14, 2007 10:21 PM PST
In reply to: ram problem

With two identical 2GB chips of RAM, the laptop will operate with the RAM in dual channel mode, meaning that data can be written simultaneously to both RAM chips, theoretically doubling the maximum possible data transfer speed, just like what RAID 0 (theoretically) does for hard disks.

Therefore, if you remove one chip, leaving only one chip behind, the RAM will then only be able to operate in single channel mode, potentially impacting performance. Always try to have identical pairs of RAM so that the RAM operates in dual channel mode which can give a performance gain over single channel RAM. So if you want, you could actually get a refund for the two 2GB RAM chips and instead buy two 1GB chips, which will be much cheaper than 2GB chips (SGD30 for 1GB compared to about SGD90 for 2GB).

P.S.: Some people did benchmarks comparing computers with RAM running in dual channel and single channel and found that this has no significant real-world impact on gaming benchmarks. However, your mileage may vary, so I would recommend dual channel still.

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Duel Boot

When I upgraded the amount of RAM in my laptop I considered buying 4GB knowing my 32bit Vista would only recocnise 3GB because in a two RAM slot machine the only way to acheive 3GB Duel Channel RAM is to install 4 and waste 1.
After reading some test reports it seems the "sweet spot" in most systems running Windows Vista 32 is 2GB RAM. In the test reports I read, over and above that seemed to acheive little if any performance gains so I opted to buy 2GB.
You could always install 64bit Vista on a seperate partition and make your machine a duel boot system, that way your 64 bit version will use all 4GB of installed RAM while giving you the option to use your 32bit OS for compatability reasons I dont know anyone who did this but theres no reason I know of why you shouldnt.

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Yeah, but why bother?
by b8375629 / December 15, 2007 12:16 PM PST
In reply to: Duel Boot

Yes you can dual boot 32bit and 64bit, but what's the point? What is to be gained by doing this? The marketplace just isn't ready for 64bit yet and with Vista as a supreme memory hog, I'd avoid it entirely. The vast majority of games (if your a gamer) out there are still 32bit programs anyway.

If you want to make your machine faster, then use 32bit Windows XP with 2GB of RAM on a Core 2 Duo system with a fast clock speed. Then sell the extra memory stick on ebay and see if you can get your money back.

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x86 limit, not OS
by AlbertW / December 16, 2007 11:18 PM PST
In reply to: Yeah, but why bother?

For what it's worth, a Microsoft rep said this was ultimately due to the x86 architecture and not the OS's fault. So supposedly it's not because of Microsoft design issues but rather Intel's.

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4gb only 3gb
by lawrephord23 / December 20, 2007 10:39 AM PST
In reply to: x86 limit, not OS

needed links to tutorials how bios drives memory paging ? how post pages memory ? how hexadecimal paging works for memory ?

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by AlbertW / January 1, 2008 1:21 AM PST
In reply to: 4gb only 3gb


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The post above is...
by R. Proffitt Forum moderator / January 1, 2008 1:23 AM PST
In reply to: Huh?

Likely from an entry level student programmer. It's best to let them stew for a while till tender.

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by denkile / December 31, 2007 7:26 PM PST

FYI for a Desktop System:
DFI nF4U, Athlon64 E4steping, XP-Pro 32bit:
_4GB actually works/functions as shown by taskmgr.exe
(Ctrl+Alt+Del>Performance) and Everest
just that XP does not display it
_Dual RAM is really twice as fast
for AMD Socket 939 with later chipsets and stepping

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