Strange behavior of v6.x

[mig]

Hi all,

I've noticed 2 fuzzy thing on my server-like rig when I choose parallel processors or round robin when I test.

Machine is completely perfect and stable and that was verified with new versions of GoldMemory, MemTest86(+), Prime95, OCCT, PC-check, BurnInTest...for days without any issue.

BUT

If I select from UEFI all cores in parallel after few minutes, in test 3. I've got xxxxxx errors and machine turn off. If I choose round robin it will stuck at 25% at 3. test, it is freezed.

If I use default CPU settings it will run for days and days without any error. Just got an erros when I use multiple cores at once.

When I am not using UEFI, but 4.3.2 version it will use all cores at once and will never shutdown, freeze, or pop up any kind error. Everything OK

Machine:

AMD FX-8300
Asus M5A97 Evo R2.0
Kingston HyperX Fury 2x8=16 GB DDR3-1866 dualchannel

Everything is on stock speeds.

What is causing this?

[David (PassMark)]

Most likely a bug in the UEFI BIOS.

Can you see if ASUS has a firmware upgrade available for the motherboard.

[mig]

Yes, I have the newest BIOS on the board

[David (PassMark)]

Although it might seem unlikely that the RAM does have a fault, it would be good to rule it out. Would it be possible to swap out the RAM (if you have spare sticks), or just test 1 stick at a time.

[mig]

If so, that errors would appear also when I use v4.3.7 (non UEFI) and select all cores in parallel, but it is not happening - it is errorless.

[David (PassMark)]

I agree it is unlikely to be the RAM at fault, but it would be good to rule it out. (V4 of MemTest is different, 32bit, code. So V6 can be expected to behave a bit different sometimes).

The most likely cause is still a BIOS bug.

If you want, send us the log file.
A log file (MemTest86.log) is automatically created and updated while MemTest86 v6 is running. This file is saved in the 'EFI/BOOT' directory in the USB drive's first partition.

[newman]

Have similar problem in test 6.
Several errors in parallel cpu mode and non in single cpu.
What is the purpose of these cpu options in general?

[David (PassMark)]

Unless your PC also turns itself off or locks up, I doubt it is the same issue.
More likely they are real errors, that you only get under heavier load.

[newman]

Parallel CPU mode makes heavier load on memory? I thought it's CPU related only.
And if it makes more load and finds more errors then why its not enabled by default?
What is the purpose of these cpu modes?

[David (PassMark)]

Older UEFI BIOS only supports single threading.
More cores in use at the same time means faster testing and it also exercises more of the silicon on the CPU and generates more heat.

Parallel testing should be used if it is available on your machine.