[smegger001]

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

[Sayrus]

ECC protects against more events than cosmic rays. Those events are much more likely, for instance magnetic/electric interferences or chip issues.

[wang_li]

In the 2010 era of RAM density, random bit flips were really uncommon. I worked with over a thousand systems which would report ECC errors when they happen and the only memorable events at all were actual DIMM failures.

Also, around 1999-2000, Sun blamed cosmic rays for bit flips for random crashes with their UltraSPARC II CPU modules.

[direwolf20]

Those random unexplainable events are also referred to casually as "cosmic rays"