The system does not see all the RAM. Windows doesn't see all RAM

Updated: 04/13/2019 Published: 06/15/2018

Description

The system detects less RAM than is installed in the computer.

Or not all memory is available to the system:

Also, the BIOS may not detect its entire volume (more often than not, only half).

Cause

1. Part of the memory is taken by the built-in video card.
2. The edition or bit limit of the operating system.
3. Software limitation.
4. Memory reservation by the system.
5. RAM malfunction.
6. Processor-side limitation.
7. BIOS error or need to update it.
8. The maximum volume limit that the motherboard supports.
9. The motherboard does not support one of the memory modules.

Solution

1. Using the built-in video card

This problem is characterized by insignificant memory allocation for the video adapter. In this case, we will observe a slight decrease in available memory, for example:

If we want the built-in video card to consume less memory, go to the BIOS/UEFI and find one of the parameters:

• Share Memory Size
• Onboard VGA Frame Buffer
• Display Cache Window Size
• On-Chip Video Window Size
• Onboard Video Memory Size
• Internal Graphic Mode Select
• Integrated Graphics Share Memory

* in different BIOS versions they may be called differently. It is also possible that other parameters may be used - in this case, you need to study the documentation for the motherboard or use a search engine.

Then we change the amount of memory reservation for the required video systems:

2. Operating system limits

Different editions of the Windows system have limitations on the maximum amount of memory used.

a) All 32-bit versions can use a maximum of 3.25 GB of RAM. This architectural limitation is the limit of what a 32-bit system is capable of. The picture will look something like this:

To use more than 3 GB of memory, you need to reinstall the system to the 64-bit version.

b) Windows editions also have limitations. For example, Windows 10 Home 64 bit will allow you to use 128 GB, and Windows 10 Pro x64 will allow you to use 512 GB. With Windows 7 the situation is worse - the home basic edition will allow you to use only 8 GB, and the initial edition only 2 GB.

More details in the tables:

If our problem is related to the edition limit, we need to update the system or reinstall it.

3. Software limitation

The restriction can be set in the system. To remove it, open the command line and enter the command msconfig- the “System Configuration” window will open (you can also use the Windows search by the window name).

In the window that opens, go to the tab and click on Extra options:

Check that the checkbox is not checked Maximum memory:

4. Setting up the basic I/O system

In order for the computer to use all the memory, in some cases, BIOS/UEFI settings may be required:

5. Maximum volume that the motherboard supports

It is necessary to check what is the maximum volume that the motherboard itself can see. To do this, you should use the instructions - it is included in the kit, and you can also download it from the manufacturer’s website. Also, similar information can be found on some online stores:

6. Memory module failure

In the event of a memory failure, the system and BIOS will not display its entire volume (usually only half). For example, if 16 GB are inserted into the computer (2 8 GB sticks), we will only see 8.

In this case, you can try to remove and reinsert the memory sticks (you can blow some dust out of them). Also, the slats can be swapped. You can also try cleaning the contacts (a regular eraser will do). Some laptops or all-in-one computers have a separate cover, opening which you can get to the memory modules, otherwise you need to completely disassemble the computer.

If this does not help, run a memory test. In the case when the test also shows part of the memory, we try to pull out both sticks and insert them one at a time - if the computer does not turn on with one of them, this faulty stick needs to be replaced, if the computer starts with all the sticks, perhaps we are dealing with a problem BIOS (step below).

7. Processor limitations

Each processor has its own limit on supporting the maximum amount of RAM. You need to go to the official website of the developer and check what maximum volume our processor supports.

8. Installing the driver for the chipset

Updating or reinstalling the driver may also help resolve the issue. To do this, we determine the manufacturer and model of the motherboard, go to the manufacturer’s website, find the page for the specific model and download the driver for the chipset. Install the downloaded driver and restart the computer.

Also, the driver can be installed semi-automatically using the DriverHub program.

9. Problem with BIOS / UEFI

Since BIOS/UEFI is responsible for collecting information about the computer, the problem may occur at the initial stage of turning on the PC.

First, let's try resetting the settings. To do this, disconnect the computer from the power source and remove the battery for 20 minutes (you can try it for the first time, 10 seconds). If this does not help, update the BIOS.

10. Module support from motherboard side

If you purchased additional memory and it is different from the second stick, you need to make sure that the motherboard supports the new module.

This can be done on the official website of the motherboard manufacturer - go to the support section and find the compatibility sheet. Among the list of equipment, you need to find the purchased memory.

11. Windows license limitation

The systems that come with computers use a strict licensing policy that limits the replacement of equipment. This can lead to a situation where, when adding memory, all of it will not be recognized.

In this case, you need to reinstall the system. In this case, a simple reinstallation over the existing system will not help - only a complete formatting of the system partition with the installation of a new Windows.

12. Rearranging memory modules

Sometimes, rearranging memory modules helps. We simply disassemble the computer, take out the modules and swap them.

13. Cleaning modules with an eraser

If the problem appears on its own, you can try to remove the memory modules from the motherboard and clean their contacts with an eraser. Afterwards we blow out the connectors on the motherboard and insert the memory into place.

If programs freeze, games glitch, or YouTube videos are slow, it's time to check your RAM usage. Perhaps the system components do not have enough space to store and process information.

How to check the amount of memory used?

Launch "Task Manager". Go to the “Performance” tab and click “Resource Monitor”.

Go to the “Memory” tab and look at the data.

Reasons for incorrect use of RAM

If Windows sees the RAM bar, then the problem lies in the following points:

1. Incorrect installation of the operating system. For PC owners with 4 GB of RAM, the 64-bit version of the system is suitable, since the 32-bit version uses a maximum of 3.15 GB of memory.

• The built-in video card consumes RAM resources dynamically, not fixedly. This means that if she needs a certain amount of RAM, she will get it.
• Motherboard limit. All motherboards have a certain number of slots for RAM sticks. If there is a free one on it, this does not mean that the motherboard will be able to use an additional bracket.
• An old version of BIOS that does not have the ability to gain full access to all resources.
• Mechanical failure of the slot or the RAM card itself. If you have the opportunity to swap the slats, do so. RAM can also be checked for functionality using the Memtest86+ program.

How to set maximum RAM usage?

In order for the RAM to be fully used, it is worth performing a number of simple steps. Launch "Task Manager". Click “File”, “New task (Run)”.

Enter “msconfig” and click “OK”.

This problem can occur on any Windows. Let's figure out why all the memory on the computer is not available.

Bit depth/bit depth and editions of Windows OS may have limitations

Due to the bit depth of Windows, there may be problems detecting all RAM. All Windows that are 32-bit (x86) cannot use more than 3.2 GB of RAM for operation. That is, even if you have, for example, 8GB of RAM installed, Windows 32bit will only be able to use 3.2GB of memory due to limitations. Also, some editions of operating systems may have restrictions. For example, Windows 7 home basic can only use 4GB of RAM!

Disable the Maximum Memory setting in MSCONFIG

Everything is simple here: if you were trying to increase the performance of your PC, you could enable the “Maximum memory” setting. It’s easy to disable it, go to Control Panel --> Administration --> System Configuration --> Boot tab --> Advanced settings --> uncheck Maximum memory!

Allocating memory to the integrated video card

Those who have an integrated video card can reserve RAM for it. To disable memory reservation for the integrated video card, you need to go to and turn off this setting there.

Look for the following values ​​in the BIOS:

• Display Cache Window Size
• Frame Buffer Size
• Int. Gfx Memory Size Select
• Internal Graphic Mode Select
• Internal Graphics Mode Select
• On-Chip Frame Buffer Size
• On-Chip Video Window Size
• Onboard VGA Frame Buffer
• Share Memory Size
• System Share Memory Size
• UMA Frame Buffer Size
• VGA Share Memory Size
• Onboard Video Memory Size

And disable memory reservation - DISABLE, NONE or set the minimum value as is.If you do not find such values, you will have to use Google and find these settings for your BIOS / UEFI.

Reserving memory for system needs in BIOS / UEFI

The BIOS settings have various restrictions on the use of RAM, and it is often because of them that Windows does not see all the RAM. Look for the following settings in BIOS/UEFI and change them:

• HPET Mode (if there is such a function) should be 64-bit;
  
• Memory Hole must be in Disabled state;
  
• Memory Remapping;
  
• DRAM Over 4G Remapping;
  
• H/W DRAM Over 4GB Remapping;
  
• H/W Memory Hole Remapping;
  
• Hardware Memory Hole;
  
• Memory Hole Remapping;
  
• Memory Remap Feature - all these values ​​must be in the Enabled state.

If you do not find such values, you will have to use Google and find these settings for your BIOS / UEFI. Very often, in this caseSimply resetting the BIOS settings helps, try this too.

Sometimes these values ​​cannot be found because the BIOS is outdated and then it would not hurt to update it. I showed how to do this in one of video.

What other problems could there be with detecting RAM?

If you have problems with the motherboard or the RAM itself, this can cause the same consequences; Windows will not see all the RAM. To identify problems it is worth doing Motherboard and RAM diagnostics.

Sometimes it helps to simply plug the RAM strips into the motherboard. Setting the RAM strips to dual-channel mode also helps.

Those who have non-original versions of Windows installed (assemblies) also experience problems identifying the entire RAM. Use original Windows distributions and you will not have such problems.

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;
• there are too many active processes running;
• the 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 are problems with connecting memory sticks or their incorrect operation. 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 a good idea to perform a memory test, for which you can use Windows' own tool (mdsched) or third-party programs like Memtest86/86+.

If problems are not identified at this stage, pay attention to the bitness of the installed Windows modification. If you have a 32-bit version, which cannot work with RAM of more than 4 GB (unless you use special tools), no matter how much memory you install above this limit, the system will still 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 will have to be copied 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 boot tab, click the additional options button and check if the maximum memory checkbox 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 components section and disable the unused ones (Hyper-V module, Internet Explorer if you use another 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 the 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.

It's clear.
I looked at the processor specification of my old computer on the Intel website - it says about it:
Instruction Set 32-bit
http://ark.intel.com/products/27438/Intel-Pentium-4-Processor-2_40-GHz-512K-Cache-533-MHz-FSB

In general, I read more on this topic on the Internet - I came to the conclusion that in order for Windows to see and start using 4 GB of RAM, software alone is not enough. That is, even server versions of Windows that have a full-fledged PAE (and install any patches there) will still not be able to interact with all the memory if the chipset in the motherboard does not have additional lines for interacting with the memory. Those. In order for all this to work, in addition to software support, hardware support is also needed. Here again, using my old computer as an example - it has a motherboard based on the i945 chipset - the instructions for the motherboard state that up to 4 GB of memory can be installed. But in reality, no matter what you make up, it’s still impossible to use all 4 GB there. We can say that the chipset is 32-bit and it will not be able to accept addresses larger than 2^32 (that’s 4 GB), i.e. physically there are not so many cells in the microcircuit for recording the address or whatever, there are not so many lines on the board... And since the entire common address space (32-bit turns out) goes not only to RAM, but also to all devices - video, sound there, all sorts of controllers, etc. - then a certain part of the RAM remains without addresses and the system cannot interact with them. It turns out that in order to use all 4 GB of memory on a 32-bit chipset, you need to have nothing else on the board except the processor, memory and chipset - no other equipment. But why then might such a system be needed? :-)
But, for example, already on the G31 chip (it seems) there are additional 4 lines for working with memory, the address space increases to 2^(32+4) = 2^36, that is, up to 64 GB (although here too in fact, it will turn out not 64, but 64 minus the amount of address space that the equipment will occupy).

In general, in the end it turns out that in order for Windows to interact with all the memory it is necessary that
1. Chipset mat. The board physically allowed the use of an address space of more than 32 bits.
2. Chipset mat. The board was able to do “memory redirection” (memory mapping) - this is when memory cells with addresses that are occupied by equipment are assigned other free addresses from the space above the first 32 bits
3. The operating system was able to use this feature. boards (as far as I understand, the ability of the OS to use this feature of motherboards is called PAE - Physical Address Extensions).

Well, the conclusion (why it doesn’t work for many) is my conclusion and maybe I’m wrong.
This patch described in the article is only the third item listed above - software. But if the board physically does not have additional lines and does not know how to do memory redirection, then it cannot earn anything.