[sznio]

What I'm wondering, even without ECC, afaik standard ram still has a parity bit, so a single flip should be detected. With ECC it would be fixed, without ECC it would crash the system. For it to get through and cause an app to malfunction you need two bit flips at least.

[ciupicri]

I think standard RAM used to have long long time ago, but not anymore. DDR5 finally readd it sort of.

[roryirvine]

Yes, 30 pin SIMMs (the most common memory format from the mid-80s to the mid-90s) came in either '8 chip' or '9 chip' variants - the 9th chip being for the parity bit.

Most motherboards supported both, and the choice of which to use came down to the cost differential at the time of building a particular machine. The wild swings in DRAM prices meant that this could go from being negligible to significant within the course of a year or two!

When 72 pin SIMMs were introduced, they could in theory also come in a parity version but in reality that was fairly rare (full ECC was much better, and only a little more expensive). I don't think I ever saw an EDO 72 pin SIMM with parity, and it simply wasn't an option for DIMMs and later.

[meindnoch]

Wrong. Regular RAM has no parity bit.