General Computing
linux memory
Updated Wed, 27 Jul 2022 00:33:57 GMT

Why is the Actual RAM Size Less Than It States?


According to the /proc/meminfo on my machine, I have 16366448 KiB of memory, which is approximately 15.6 GiB. But my two RAM sticks should have 16 GiB in total. Why so?

Solution

Some RAM at different measure stages can be taken by:

  1. CPU graphics card
  2. text mode of terminal (legacy from MS-DOS)
  3. BIOS/UEFI
  4. operating system (both Windows and Linux) - kernel and other
  5. dedicated graphic card (not in CPU)
  6. other firmware depending on hardware

And that's why you can't see whole memory even if it is there.

About RAM you can be sure that it is there, I mean if you have 16 GiB of RAM, you strictly have 16*1024^3 = 17179869184 bytes.


References