I recently had an interesting experience with bad non-ECC RAM. The only effect I saw for many months was a frequently crashing web browser. I was very annoyed and downgraded to the firefox LTS release to try to solve the issue. The problem went away for a while, then came back. Seemingly erratic the problem could resurface only to disappear a while later.

Eventually I got a corruption in a large Git repository with photos. First I suspected a disk error but reruns of "git fsck" reported different bad objects, run to run. How odd, so I ran memtest86 and it reported a bad 32 MB memory region at offset 4 GB. Never saw any kernel issues or other instability. Booting up the computer does not use up 4 GB of memory (Linux) but starting a bloated web browser does.

The computer is stable after mapping away the bad memory region by using GRUB_BADRAM. That was an new takeaway for me, a machine with ECC memory can do this bad blocks mapping automatically. It's not just beneficial in correcting single bit errors.

I would love to have ECC memory in my machine. I used it for my previous build in 2012 but I think the situation has gotten worse since then. Bigger price difference and ECC memory is not even available at the same clocks as non-ECC memory.