Why only 3 available from 4GB of RAM? Factors influencing the determination of the total amount of memory

By | 07.04.2016

People often ask the question: why the four (six or eight) gigabytes of RAM installed in your computer, available only 2.23 (3.25 or 2.87, etc.)? Listed below are the possible causes of an incomplete definition of RAM.

Why does my computer does not see any part of the RAM

1. A 32-bit operating system.


Any 32-bit OS will «see» no more than 4 GB of RAM. Most — from 3.15 up to 3.5 GB. And here it is not so important, XP, or this «eight». This is due to the specifics of the memory address space allocation. Accordingly, in order not to fall into such a situation, it is necessary to use a 64-bit of Windows.

2. The computer uses the integrated video adapter

Part of memory for their needs may «cut» an integrated (or «built-in») card. Very often it is found in laptops. This situation is the norm. And if the remaining amount of RAM is not enough for you, the advice is only one: to increase its volume by adding or replacing modules.

It is also important to understand that:

  • different integrated graphics cards taken a different amount of RAM;
  • one and the same graphics card is able to take a different amount of memory, depending on the volume of RAM installed in your computer. For example, when there was 2 GB of RAM, 512MB graphics card took away. When installed 4GB — 1GB graphics have become cut off.
  • there are hybrid video cards that have their own memory, but also able to expand it at the expense of borrowing memory from RAM.

Because of these two reasons, it is sometimes quite difficult to understand why it is such an amount of available RAM. It may be that from 6 gigabytes installed the Windows 32-bit «saw» 3.25 GB and the graphics card «cut» of this volume still 512MB. As a result, in the system properties will be written 6GB (available 2.73). The solution of this problem will be combined again, replacing the operating system on 64-bit and, if necessary, the RAM capacity.

3. OS publication restrictions on the maximum amount of RAM

Younger editions of Windows 7 and Vista have restrictions on the use of RAM. For example, Windows 7 Starter works only with 2 GB of the RAM, Home Basic with 8GB x64-, x64- and Home Extended 16GB.

4. Part of the memory is faulty or there is no contact

Turn off the computer. Disconnect the power cord from the stationary PC or remove the battery from the laptop. Press the power button a few times to remove the charge from the capacitor.

Remove any memory modules, clean their contacts eraser, then clean them with alcohol. Install straps into place and check that all are determined by the system. This is conveniently done in CPU-Z free program. Click the SPD tab. On the left side of the window there is a drop-down list that displays information about the installed RAM strips in each slot:


If the fields are displayed when you select a particular slot, then there is not a module, or it does not work.

5. The modules are installed incorrectly

In some models of the motherboard slots may not work until the busy priority slots. Therefore, such nuances should be specified in the manual for the motherboard (the manufacturer’s website or in the brochure).

6. The problem of compatibility of modules

Check the operation of separate strips using Memtest86 +


If each module alone is working correctly (as determined in the system, its volume is displayed correctly, there is no error in the tests), and when several together one is not defined, then there is a compatibility problem between the strips themselves. To avoid this, try to establish exactly the same modules.


Once again about the most important. To the operating system used the RAM to the maximum, it is recommended to install the 64-bit editions of Windows such as the Professional. When it comes to modern operating systems (Win 7, 8.1 and 10), with the installation of a 64-bit version is no problem. And if you have a choice, feel free to choose that option.

But XP x86 and XP x64 — it’s actually a different system with different kernel versions. And Windows XP 64 bit edition is considered to be quite volatile. Therefore, it is advisable either to install Windows 7 / 8.1 / 10 (if the computer is designed to work with one of them), or to leave XP 32-bit.

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