Why is 3 available out of 4 RAM? Not all RAM is available: how to use its full capacity

The other day my friend asked me to help him figure out his problem: Windows 7 on his Samsung laptop The R525 reported that it saw 3 GB of installed memory, but only 764 megabytes were available. The laptop, of course, worked slower than we would like. You can check how much memory Windows sees by right-clicking on “My Computer” and selecting “Properties”. The picture will be something like this (the screenshot shows what was achieved as a result of solving the problem):

A search for the phrases “3 GB installed, 1 GB available” and “Windows shows more memory installed than available” showed that the problem is widely known, but can be caused by many reasons.

What was checked first:
2 DIMM PC-133 are installed, one is 1 GB, the second is 2 GB BIOS sees all these 3 GB, the system sees them too;
Rearranging DIMMs does not change anything;
Our Windows 7 is 64-bit, so it should definitely see more than 3 GB of memory;
Windows 7 Home Basic supports up to 8 GB of memory, so there shouldn’t be any problems depending on the system version;
the “Resource Monitor” program (click the “Start” button and in the “Search programs and files” line just write - Resource Monitor”)* says that more than 2 GB is reserved for some devices;
in the msconfig.exe program on the Boot->Advanced tab, the “Maximum memory” checkbox is NOT checked; This is how it should be - to use the maximum amount of memory, the checkbox must be unchecked.

The problem could lie in the video card driver settings. The fact is that modern video cards often either do not have their own memory at all, using the system memory for their own purposes, or have a minimum of memory on board, and for displaying images from high resolution or with a large number colors also use system memory. Laptop BIOS allowed me to “take a bite” from system memory no more than 512 MB, so reserving an additional 1.5 GB could be attributed to the driver.

In this Samsung models uses integrated with motherboard ATI video card Radeon 4250. Had to download new driver this video card, but installing it did not help: the driver of this video card does not have settings indicating how much system memory the driver can “eat up”. In principle, some video cards are able to share memory with the system, marking it as reserved, and the resource monitor understands this, displaying such memory as a gray bar. An example display is shown in the figure below, but for a different system, just to give you an idea of ​​what it looks like.

The system can use the memory shared between the video card and the system until the video card needs it, and as soon as the video card requests it, the system will be forced to release it. However, the amount of such shared memory, even if it exists, is usually limited to no more than half of the available memory, more often - noticeably less.

Thus, our case was out of the ordinary. Then additional research was undertaken: instead of the old memory modules, a new module 4 GB in size. The amount of available memory has increased to 2.75 GB. This already looked like an automatic “biting off” of memory by the video card (exactly about 1.25 GB should have been reserved, a number of sources on the Internet spoke about the formula used “half the system memory minus 512 GB, which for us for 4 GB of system memory gave would be 1.5 GB).

Suspicion fell on one of the DIMMs. And it’s true: when I tried to boot with only one old module of 2 GB in size, the laptop refused to boot. It turned out that the SPD chip on it, which tells the system the configuration of the module, was alive, and the memory itself was faulty, and therefore Windows excluded it from operation.

After replacing the faulty 2 GB module with a new 4 GB module, the system returned to normal life, and the picture of the memory properties became as shown in the figure at the beginning of this article.

Note to the owner: what Windows shows as “installed memory” does not always reflect the amount of working memory. If there is a noticeable difference (more than 40%) between the installed and available memory check boot settings using msconfig, and also monitor the health of memory modules. In addition, it is better not to buy such video cards or laptops with integrated video cards that voraciously consume system memory.

If you decide to upgrade your computer by adding some RAM, it may happen that after installing it, the system will display the amount of memory that you installed, but not all of it will be available, and this is despite the fact that a 64-bit operating system is installed system.

Just recently, I had to face a similar situation. In general, to a computer that had 2GB of RAM installed, it was necessary to add another stick with the same amount of memory.

As a result, after installation, the system saw all 4GB of RAM, but it indicated in brackets that only 3GB was available. But the most surprising thing was that Windows 7 x64 was installed on the computer, therefore no restrictions should be imposed on the RAM, as is usually the case on x32.

Having started to figure it out, I eventually found a solution that helped me return my memory to its place and will gladly share it with you. Below in the article I will show what you can do if you see only 3 GB of RAM on Windows x64 instead of 4, 8 or 16 GB of RAM.

On a 64-bit system, instead of 4, only 3 GB of memory is available, what should I do?

Of course, the first thing I thought was that it was all in the system, perhaps some kind of crooked assembly was installed, but after Windows reinstallation nothing has changed from the licensed image and only 3 GB of memory was available as before.

Based on this, we can assume that the problem is in the hardware or in the BIOS settings.

Once in the BIOS, I started looking in the settings for any parameters that were somehow related to RAM.

After spending about 15 minutes turning different parameters on and off, as well as checking the results, I finally found something that helped me.

This is a parameter called " Memory Remap Feature", precisely after I changed its value from " Disable" to " Enable", in the system properties the memory began to be displayed normally, that is, all four gigabytes of RAM were now available.

How to find this parameter? Below I will show a clear example of where I managed to find this function. Of course, I understand that today there are quite a lot of different motherboards that have appearance different. But for now I’ll stick to my example, and then, if possible, I’ll add something new. I can recommend looking for it in the chipset settings, most often that’s where it is located.

So, we reboot or turn on the computer and enter the BIOS, let me remind you that standard keys to enter BIOS " Del And F2", if nothing suits you.

Go to the tab " Advanced" and using the navigation arrows go down to the section " Chipset" or maybe " Chipset Configurations».

The next step is to go to the “ North Bridge Configuration" By the way, many people may not have this point; if so, it’s okay, skip this step and move on.

Having reached the right place select the option “ Memory Remap Feature", by pressing "Enter", set the value " Enable».

After, confirm the selected value and restart the computer, saving all changes made by pressing the F10 key.

If earlier on a 64-bit system you only saw 3 GB of RAM instead of 4, now everything should change and after booting the computer, the system properties will show that all 4 (or more) gigs are in use.

At least it helped me, so the advice has been tested in practice and that is why I recommend using it first of all.

What else can you do if only three gigabytes of memory are available instead of four?

Everything is clear with the “Memory Remap” function, but what should those who don’t have it do? Yes, it may be that you won’t find this item at home, especially for laptop owners.

The point is that this function can be built into the BIOS, even if there is no such parameter there. In such cases, of course, it is recommended to use the latest version. And only after this “Memory Remap” will begin to fulfill its functions.

You can also look for the parameter “ Memory Hole" its value should be set to " Disabled».

HPET Mode Another parameter that is recommended to be checked and set to “ 64-bit».

Opening through the window Execute».

Move to the tab "" and click on "".

And here we uncheck the “” parameter.

Apply the new settings and restart the computer.

Also, some amount of RAM can be used by the built-in video. For example, if your monitor cable connects next to USB ports, then you are using embedded video, therefore for it full-fledged work a certain part is taken from the total amount of RAM and transferred GPU, and that's why instead of 4 GB, you can see that there is slightly less memory available, for example 3.5 GB. Here you will have to measure yourself or buy a discrete video card.

There is also information that even with a separately installed video card, the processor continues to take up RAM for the needs of integrated video. In this case, you need to change the processor graphics value to the minimum or disable it completely by setting the value for integrated graphics in the BIOS to Disable (PCI or Auto). After the reboot, all missing RAM should return to its place and be displayed in full.

And of course, there is a possibility that instead of the installed amount of memory you see much less due to the fact that your motherboard simply does not support, for example, more than 3 or 4 GB, but this usually happens on quite old motherboards .

As you understand, there can be a lot of reasons for displaying 4 GB of memory instead of 3 GB, and everyone’s solutions may be different. In this instruction, I showed you what really helped me and what else you can try to get out of this situation. If anything, as always, I look forward to your comments, and together we will look for the answer to your question.

Familiar to many users. When you call the system properties window, the full volume is displayed, but for some reason after it it is indicated that there is slightly less memory available. It’s even worse when the user knows exactly how much RAM he has installed, but only 50 percent or less is available. Why this happens and how to use the maximum amount of RAM will be discussed further. But first, let's briefly look at the main reasons for this phenomenon.

Why is not all RAM available?

So, the fact that Windows operating systems sometimes produce indicators whose values ​​are obviously less than the total amount of installed RAM may be associated with a number of reasons, among which the most significant are the following:

• A 32-bit system is installed that does not support memory more than 4 GB;
• maximum is not supported by the motherboard;
• in the system parameters there is a limit on the maximum amount of RAM used;
• Memory redistribution settings are set incorrectly in the BIOS;
• memory is partially reserved for built-in video adapters;
• too much running active processes;
• installed strips are damaged, their performance is impaired, or they are connected incorrectly;
• memory usage is blocked by viruses.

It’s worth saying right away that issues related to viral exposure will not be considered in detail. Here we can advise you to just perform a scan, just in case, using portable antiviruses or similar programs that have bootloaders at their disposal.

How to use all installed memory in the simplest ways?

Much more important issues when not all RAM is available, there are problems with connecting the memory sticks or their incorrect work. First, make sure that the motherboard is designed for the installed volume, and also check the tightness of the insertion of the strips into the corresponding slots. It would also be useful to perform a memory test, for which you can use your own Windows tool(mdsched) or third party programs like Memtest86/86+.

If problems are not identified at this stage, pay attention to the bit depth installed modification Windows. If there is a 32-bit version, which cannot work with RAM of more than 4 GB (unless you use special means), no matter how much memory you install beyond this limit, the system still does not recognize it.

The optimal solution would be to install a 64-bit version of Windows. But in this case, previously installed programs may not work, and important files you will have to copy it to another logical partition or to removable media.

Sometimes it happens that not all RAM is available due to incorrectly set memory usage options in (msconfig).

In the configurator, on the download tab, click the button additional parameters and check if the maximum memory option is checked. If there is one, remove it, save the installed options and reboot the system.

As is already clear, part of the memory can be “eaten up” by a huge number of active background processes and services that are not visible to the user. First, disable all unnecessary components in startup (in Windows 7 and below, the corresponding tab in the configuration settings is used for this; in higher versions, “Task Manager”).

Just in case, look at the active components of the system in the Programs and Features section and disable the unused ones (Hyper-V module, Internet Explorer, if you use a different browser, print service, if you don’t have a printer, etc.). Similarly, you can set the startup type to disabled for some other services (services.msc), but in this case you need to know exactly what can be deactivated and what cannot.

There is little RAM available: what settings can be changed in the BIOS?

If the problem remains after applying the solutions described above, go to the settings of the primary BIOS/UEFI systems and check the memory settings, which should contain an item containing the words Remapping or Remap (redistribution).

If you have 64-bit Windows and have more than 4 GB of memory, set it to Disabled. Otherwise it needs to be activated.

If not all RAM is available due to reserving additional space for the video card built into the motherboard, set this item to a value that corresponds to the adapter’s memory capacity (you can find it on the monitor tab when calling the DirectX - dxdiag dialog). This is done by changing automatic detection(Auto) to one of the available options (32, 64 or 128 MB).

Patching 32-bit systems

Finally, you can use all memory above 4 GB on 32-bit systems using the ReadyFor4GB utility. First, the executable EXE file of the same name is launched from the application folder, and then the Check and Apply buttons are pressed. After this, similar actions are performed for the ntkrnlpa.exe object. The AddBootMenu.cmd file is then launched and confirmation that the command has been executed is given. After the reboot, if a menu appears with the bootloader, Windows is selected.

Note: all actions are performed solely by running files as an administrator at your own peril and risk, since system performance after using this method is not fully guaranteed.

Some users continue to ask why they have, for example, 8 GB of RAM, but the system sees only 4 GB, or maybe even less. The answer to the question is very simple - this only happens with 32-bit systems. Whether you have Windows XP, Windows 7 or the current “ten”, but with a 32-bit architecture, it will not see more than 4 GB.

When viewing system properties, you can see even less available RAM, why is this happening? The answer is simple, part of the so-called address space goes to servicing connected peripheral devices. The video card turned out to be the most useful. Although some devices do not even use RAM. The amount of address space depends on the chipset and other parameters, for example, BIOS, computer configuration.

The system does not see part of the RAM

The only way to get rid of this problem is to reinstall the OS to a 64-bit version. Then you will have more than 4 GB available.

There is also one trick to the system. Press Win+R and enter the command msconfig. Next, the “System Configuration” window opens. Go to the “Download” tab and click on the “Advanced options” button there.

Uncheck the box "Maximum Memory".

Solution option number 2

It happens that devices for the computer configuration take up some of the memory, but not very much. Therefore, there is no need to worry about this.

Another option is to make sure which one is supported system board. But this applies more to old technologies.

Still needs to be included in BIOS function Memory Remap Feature(also has names: Memory Hole Remapping, H/W Mem Remap And H/W memory hole Remapping). After that we install a 64-bit system. Sometimes these options are already enabled automatically on modern boards, so you can just make sure.

If you actually have less than 4 GB of RAM on a 64-bit system, then the Memory Remap Feature parameter should be disabled in any case. Not only will the available capacity become even smaller due to this, but some devices will also freeze, which especially affects simulation and gameplay.

It happens that the BIOS does not see the required amount of RAM, then it is worth updating it. This is a risky business and should be approached carefully and cautiously. Instructions for updating can always be found on the official website of the motherboard.

More materials:

If in BIOS installed modules are detected, but not in Windows, then you should check the manual for motherboard. It usually says about connecting specific RAM modules, for example, which mode is better - single-channel or dual-channel. On the official website you can find out about the models that may suit you and the connection option.

If the system does not see the RAM, then this may be due to incorrect set value power supply, as well as due to faulty modules. Moreover, if one of the strips fails, then the system may not start at all, then you need to get rid of it.

Let's sum it up

So, we figured out why the computer does not see RAM, as well as a certain amount of it. I’ll describe point by point what needs to be done if this happens:

1. Reinstall the OS to the 64-bit version;
2. In System Configuration, uncheck the “Maximum memory” item;
3. Check the maximum amount of RAM on the motherboard;
4. Check the serviceability of the RAM modules;
5. Rearrange the RAM strips;
6. — instructions on the official websites of motherboards;

You can also clean your computer from dust and dirt. Wipe the contacts on the RAM modules and clean the slots. I hope this article helps you!

One day I had to assemble a computer for my friends. I do this extremely rarely, but since I am a “computer geek”, I also have to repair computer furniture :) In general, I used the following components for assembly:

Motherboard ASUS M5A97 R2.0;

AMD FX-8350 processor Black Edition, OEM;

Operational DIMM memory DDR3, 8GB (2x4GB), Kingston HyperX FURY blue;

Cooler Zalman CNPS10X Performa.

After I assembled everything, I didn’t see another 4 GB of RAM in the BIOS, i.e. instead of 8, there were 4GB. Having rummaged through the settings, I saw that the motherboard “sees” both memory sticks, but for some reason its final value was 4GB. Windows installation It didn’t bring any clarity, but made it even more confusing. In particular, in Properties of computers there was " Installed memory (RAM): 8 GB (3.90 GB available)".

After looking at the resource monitor, I finally came to a dead end, 4 GB was occupied by “Reserved Equipment”.

I began to figure out step by step how to solve this problem and I will describe all my thoughts and actions step by step from the simplest and obvious way to dancing with a tambourine. Please note that if in your case the BIOS does not “see” part or all of the RAM, then of all the methods, pay more attention to setting up the BIOS and the hardware. If the entire amount of RAM is available in the BIOS, but not in Windows, then among all the methods listed below, select only those that relate to Windows settings.

Check the bitness of the operating system.

First of all, in the system properties, look at the bit depth operating system. Don't forget that 32-bit Windows systems there is a limit of 4 GB of RAM and even if you set it to 16 GB, the computer will not see it (there are workarounds, but that’s not what we’re talking about now and they don’t always work correctly).

If you want to use more than 4 GB of RAM, you must reinstall the system to 64-bit.

Your version of Windows has a RAM limit.

Each Windows version has its own limit of RAM with which it can work, for example:

Maximum available amount of RAM on Windows 7

Maximum available amount of RAM in Windows 8

Therefore, first of all, check.

Check your motherboard's limitations.

Each motherboard has limitations in the amount of perceived RAM. Older ones can see a maximum of 4 GB of memory, others 16 GB, and there are already those that can work with 32 GB or more. Therefore, look at its capabilities in the documentation for the motherboard or on the manufacturer’s official website. Also note that the motherboard supports the operating frequency of the higher RAM.

Make sure there are no restrictions when loading Windows.

There are cases when restrictions are set on booting Windows, so some of the RAM may be inaccessible. To check this, press the key combination “Win” + “R” and enter “msconfig” in the line.

Then open the "Download" tab, click the "Advanced options" button.

In the window that opens, make sure that the checkbox next to the “Maximum memory” line is not checked.

You can try to enter the size of RAM you use in this field. In my case, this did not help; after I rebooted the computer, the check mark remained and the value became 0.

Make sure the memory is working.

There are times when the RAM has failed or you have acquired a defective one, so check its functionality. Attention!!! All manipulations with RAM strips should be performed with the computer turned off. Take out all the memory sticks and plug one into the same port one by one, after changing each stick, turn on the computer and in the BIOS or in Windows, make sure that the computer sees this memory stick. Or, on another work computer, check each strip or all together.

Shuffling RAM sticks.

For dual-channel operation of RAM sticks, it is recommended to use the same manufacturer and even the same model and the volume itself. If you are using different manufacturers, in this case, you can experimentally change the connector, connect the strips and determine the sequence in which the computer sees all your RAM.

BIOS update.

It is also important which BIOS version is used on the motherboard. Very often, updating the BIOS leads to solving related problems, including the ability to “see” RAM. Here's an example how to update firmware on ASUS motherboard .

In my case, unfortunately, even this method did not help, although for some reason I was sure that it would help.

Reset BIOS settings.

Another important point is resetting the settings to factory settings in the BIOS. Someone may say that they have never changed anything there and why reset something there. In fact, I know of cases where resetting to factory settings actually solves problems for which the solution is not obvious. In order to reset the settings, press the "Exit" button in the BIOS and in the menu that appears, select "Load default settings" or remove the battery on the motherboard for a few seconds and put it back.

Cleaning the computer and checking connections.

One more in an effective way make your computer see all the RAM - clean the RAM sticks and ports from dust. Also, don’t forget to clean the processor, pull it out of the socket, and check if the legs are bent. Many will say that this method is the most ineffective, especially those who collect new computer, like me :) But he helped me. It turned out that either I inserted the processor incorrectly (although I can’t imagine how you can insert it incorrectly without breaking several legs), or I overtightened the bolts holding the cooler (I think this version is more likely to be true), or the computer decided I don’t know that I would have given him a few more hours. But only after I removed the cooler, pulled out and reinstalled the processor, and installed it without tightening the cooler bolts too much, everything worked and the BIOS, and with it, Windows saw the entire amount of RAM.

I really hope that this article will help you in solving problems related to RAM and you will spend less time fixing it. I would be grateful if you share your method of solving RAM-related problems in the comments.