How to diagnose RAM?

Solution 1:

We run Memtest86+ against new systems for 48-72 hours, and over the years we've caught plenty of errors that didn't show until the 2nd or 3rd day. A couple/few passes just aren't enough.

Also, don't mix ECC and non-ECC, and yes, you'll probably have to remove/juggle/retest the RAM modules to find the culprit.

Solution 2:

Remember that segfaults are typically due to programming bugs like buffer overrun, use after free and null pointer dereference.

Solution 3:

One more suggestion, about Memtests86+. Memtest will check all the memory for sure but sometimes the harware failure only shows when the temperature conditions of the machine reach certain levels. And memtest doesn't stress the disks and other parts of the system.

If you think that temperature could be a problem try to run memtest under worse temperature conditions than the usual.

Solution 4:

After having looked at the BIOS settings, there was an alternative "System memory multiplier" which was set to 12. I changed this setting to "Auto", the crash does not happen any more. So, I thought it might help for others having similar issues.