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Current Memtest86 v4.3.7 (BIOS mode) doesn't see memory above 4GB (8GB installed)

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  • Current Memtest86 v4.3.7 (BIOS mode) doesn't see memory above 4GB (8GB installed)

    I have a problem with Memtest86, running as v4.3.7 presumably due to the computer not supporting UEFI. What is probably the same problem was reported in thread "Why is memtest86 not seeing all my memory ?". 2014 Clevo W670SZQ1 64-bit Pentium laptop with single 8GB SODIMM. Machine works properly save occasional BSODs on waking from sleep, and all software recognises 8GB RAM in Windows and Linux. When booting from a Memtest86 CD, downloaded as v7.4, Memtest86 runs as v4.3.7, presumably due to lack of UEFI support. However, RAM is reported by Memtest86 as about 3500MB (I think it was 3517MB), rather than the real 8GB. The tests started automatically on boot run with zero errors, but RAM always shows as 3.5GB. I know that 32-bit BIOS-mode Memtest86 is supposed to see all memory by using PAE, but this doesn't seem to be happening, the notorious PC architecture 4GB limit (usually less ~500MB used by the system) seems to be operative, with PAE not working.

    I can run Memtest86+ 5.1 (a different fork, apparently no longer updated) from CD with no trouble; it recognises all 8GB of RAM, and finds no errors.

    Can anyone shed any light on this? I have the impression that Memtest86 4.3.7, 32-bit version, BIOS mode, is not likely to be updated, though the UEFI version is - is there anything I can do besides changing to Memtest86+ ?


  • #2
    2014 isn't that long ago. You should be able to get V7 running with UEFI (rather than worrying about V4).



    • #3
      Thanks for response. I've already done the necessary testing with MEMTEST86+, so won't try again in UEFI mode for now. It's just something to be aware of, simply booting from an ISO is not the most appropriate way to go. My machine does support UEFI mode, it just has to be selected in the startup settings. I'm always a bit nervous about changing disc settings which could, worst case, not be simply reversible.