It’s a lot further than this though with unbuffered RAM, registered RAM in the mix affecting performance and such. Error detection and error correction are diff

It’s a lot further than this though with unbuffered RAM, registered RAM in the mix affecting performance and such. Error detection and error correction are different and require different levels of parity codes. Standard RAM at one point (SIMMs in the 90s) detected errors but won’t ever correct them. ECC can detect more but error patterns and now correct error patterns up to so many bits. The issues are more subtle beyond hardware though - your OS kernel has to understand the detection from the BIOS / EFI and if the motherboard manufacturer decided not to opt for wiring in the checksum fail signal you will run blind to data corruption that’s potentially really subtle on typical consumer hardware. With some BIOSes RAM failures result in a hard panic and will hard reboot the machine (the idea being a crash is better than continuing with an error). For me, ECC (both UDIMM and RDIMM) today are so inexpensive it’s a no-brainer for builds for business.