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salvia
Asked: 2016-06-17 06:32:51 +0800 CST

Help me understand memtest in my laptop

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I'm having problems with my old laptop: Ahtec clevo m7xsun from 2009, xubuntu 16.04 64 bits, kernel 4.4.0.25 and upstream 4.7.0.22 for testing. There are 4 GiB of installed RAM in 2 modules. Sometimes the BIOS detects the whole 4 GiB, sometimes just 2. I have exchanged the modules several times, so I don't believe one of the modules is broken. I was suggested to run memtest, which I did, and as you can see in the picture, after having finished a first pass in almost 2 hours, it didn't detect any errors.

enter image description here

I marked 3 points in the picture: 1, 2 and 3:

1: 2048M - 3070M 1022M of 4093M: the only thing I understand is 4093M (4 GiB RAM, my total ammount of RAM. What do the other numbers indicate?

2: Please notice this is a dual core laptop (2 DUO CPU), this has to do with question 3.

3: If my laptop is a dual core one, why does memtest show: cores: 1 Active / 1 Total (Run: All)? shouldn't it indicate 2 total? and if it is running All, well, memtest is only detecting one core out of two, and something is wrong with my laptop.

memtest

1 Answers

  1. Question 1. RAM

    It is suggested that you read this message carefully.

    It says; Testing 2048M - 3070M : 1022M of 4093M This means that currently MemTest is testing memory block from 2048M to 3070M which is of 1022M size. Hence it says 1022M of 4093M. No issues here.

    Question 2 and 3. CPU

    Core 0 (SMP disabled) means it is using Core 0 (first core). SMP for symmetric multi-processing is disabled meaning it will not use multiple cores. This is not a problem.

    Next and importantly, you should NOT depend on the MemTest86+ for CPU core counts. This is memory testing library and it just uses CPUs to execute this testing. For truly checking CPU details, when running Ubuntu, go to terminal (Ctrl+Alt+T), and run,

    lscpu

    You will get something like this;

    lscpu

    Another command is nproc (this gives total processing units, depends upon hyperthreading). Since your CPU does not have hyperthreading this will report the total cores.

    nproc

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