Why 2.66 GB usable in 4 GB ram?

windows windows-10 memory 64-bit ramdisk

8,438

This is to do with Memory Mapped I/O.

Your computer will map areas of memory in order to access other devices quickly. In your case, your display is mapped to 1473 MB which means, yes, you do have 4GB of RAM installed however 1473 MB is reserved for Display operations. Normally, on-board graphics will take a larger slice of your RAM than a dedicated card however its not just display that can take out a chunk of RAM. The memory which isn't mapped is your available; as in available to the OS solely.

If you would like to look into this further check this out Memory Mapped I/O

8,438

Avik

Updated on September 18, 2022

Comments

Avik over 1 year

I am having windows 10 pro 64 bit OS,With 4 Gb RAM. But in memory section its showing 2.66 GB usable. Why? doing some research(Googling) I found that 32 bit machine can't utilize the full RAM. But though I am having 64 bit machine, still why its showing 2.66 GB usable? I tried a tweak through MSConfig → Boot → Advanced option → unchecking but nothing is working.

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System Information
------------------

      Time of this report: 6/3/2016, 08:39:50
         Operating System: Windows 10 Pro 64-bit (10.0, Build 10586) (10586.th2_release.160104-1513)
                 Language: English (Regional Setting: English)
      System Manufacturer: LENOVO
             System Model: 20351
                     BIOS: InsydeH2O Version 03.73.069ACN28WW
                Processor: Intel(R) Core(TM) i3-4030U CPU @ 1.90GHz (4 CPUs), ~1.9GHz
                   Memory: 4096MB RAM
      Available OS Memory: 2722MB RAM
                Page File: 3268MB used, 1885MB available
              Windows Dir: C:\WINDOWS
          DirectX Version: 12
      DX Setup Parameters: Not found
         User DPI Setting: Using System DPI
       System DPI Setting: 96 DPI (100 percent)
          DWM DPI Scaling: Disabled
                 Miracast: Available, with HDCP
Microsoft Graphics Hybrid: Not Supported
           DxDiag Version: 10.00.10586.0000 64bit Unicode


---------------
Display Devices
---------------
          Card name: Intel(R) HD Graphics Family
       Manufacturer: Intel Corporation
          Chip type: Intel(R) HD Graphics Family
           DAC type: Internal
        Device Type: Full Device
         Device Key: Enum\PCI\VEN_8086&DEV_0A16&SUBSYS_380C17AA&REV_0B
     Display Memory: 1473 MB
   Dedicated Memory: 112 MB
      Shared Memory: 1361 MB
       Current Mode: 1366 x 768 (32 bit) (60Hz)

100rabh almost 8 years

superuser.com/questions/35731/…
Hefewe1zen almost 8 years

It also depends on your hardware. What are your specs?
Ƭᴇcʜιᴇ007 almost 8 years

Did it EVER show all 4GB of RAM? Does all the RAM capacity report properly in the BIOS?
Zoredache almost 8 years

Need details about your hardware. Crappy onboard video cards can steal some of the system RAM. Some hardware can't actually handle a 4GB. A quick test would be to boot a Linux livecd. If i t also reports a limited amount of RAM, then the problem is somehow related to your hardware.
Avik almost 8 years

I edited my question and posted the hardware specs.In BIOS its showing 4096 MB ram.I upgraded from windows 8.1 to windows 10 few months back, though that time i didn't check ram usage. I will boot linux live cd and post the result here.
100rabh almost 8 years

In BIOS its showing 4096 MB ram what motherboard do you have? Seems like it's capped to 4GB right there.

Avik almost 8 years

According to the concept does it mean if I increase RAM memory(probably another 4GB stick ) then I will have 8000-1473=6527 MB usable memory?
Harvey almost 8 years

Yes, in theory. There is a certain amount of RAM that your hardware will be mapped too, your OS will have the rest.