Question Computer can only use half of the installed RAM

Jul 10, 2021
I have a computer with one 4 GiB DDR4 RAM stick installed. Initially it worked fine, but lately something strange has happened. Now the computer can only use half of the RAM, but apart from this it still works fine. Both the computer and operating system are 64-bit.

In the UEFI and in the installed operating system (Manjaro Linux), all of the RAM (3.7 GiB) is detected, but the operating system can only use half of it. It shows up in Conky as 100% used (not including cache and buffers) when only half of it is actually in use.

When I boot into MemTest86, only half of the RAM is detected, and it shows no errors when it tests it. Similarly, when I boot into any live Linux distribution, only half the RAM is detected, but everything else works fine.

I've tried removing and reinserting the RAM, but it didn't help.

What might be the cause of this problem?