RAM Bitflips and ECC

Comments discuss bit flips in computer memory, primarily caused by cosmic rays, radiation, or hardware issues, and the importance and limitations of ECC memory for error detection and correction.

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Keywords

RAM DIMM DDR4 CRC libpython.so GPU AMD DRAM L3 ECC ecc ram flips cosmic bits errors bit rays memory error

Sample Comments

timthorn Dec 2, 2024 View on HN

They don't - random bit flips are expected over time. ECC memory is a thing because of this, but cosmic rays can strike the processors too.

aborsy Oct 16, 2022 View on HN

How frequent are bit flips in RAM, causing errors undetected by non-ECC RAM?

H8crilA Dec 25, 2022 View on HN

This problem has no ultimate solution. I've seen all components flip bits, CPUs, networking cards, RAM, most often you just can't know for sure what did it. You can remedy it a bit (like with ECC), but ultimately there will always be corruption if you process hundreds of petabytes of data. Get used to it, your computer executes an instruction with a probability extremely close to 1, but not equal to 1.Deep in the archives of a well known tech company is a very well documented case o

orangepurple Oct 19, 2023 View on HN

Is ECC memory vulnerable to these kinds of bitflips?

splitrocket Aug 24, 2015 View on HN

Cosmic rays flip bits all the time:"one error per month per 256 MiB of ram was expected"http://stackoverflow.com/questions/2580933/cosmic-rays-what-...

lukan Dec 18, 2025 View on HN

Rowhammer, cosmic bitflip or hardware or just compiler bugs come to mind.

Waterluvian Jul 4, 2021 View on HN

Are “cosmic rays” actually the only or primary way bits get flipped? Or is it just a stand-in for “all the ways non-ECC RAM can spontaneously have an erroneous bit or two”?

smegger001 Jan 23, 2026 View on HN

if cosmic ray bit flips were so rare then ecc ram wouldn't be a thing.

Rebelgecko Feb 19, 2017 View on HN

Not just faulty RAM. As far as I know, all modern RAM is going to have bitflips every once in a while (it even happens with ECC RAM)

abritinthebay Mar 20, 2018 View on HN

Why? The error seems reasonable (radiation can and could have flipped bits, I've done it on sensitive hardware with a camera flash).