I got into overclocking both regular and ECC DDR4 ram for a while when AMD’s 1st gen ryzen stuff came out, thanks to asrock’s x399 motherboard which unofficially supporting ECC, allowing both it’s function and reporting of errors (produced when overlocking)

Based on my own testing and issues seen from others, regular memory has quite a bit of leeway before it becomes unstable, and memory that’s generating errors tends to constantly crash the system, or do so under certain workloads.

Of course, without ECC you can’t prove every single operation has been fault free, but as some point you call it close enough.

I am of the opinion that ECC memory is the best memory to overclock, precisely because you can prove stability simply by using the system.

All that said, as things become smaller with tighter specifications to squeeze out faster performance, I do grow more leery of intermittent single errors that occur on the order of weeks or months in newer generations of hardware. I was once able to overclock my memory to the edge of what I thought was stability as it passed all tests for days, but about every month or two there’d be a few corrected errors show up in my logs. Typically, any sort of stability is caught by manual tests within minutes or the hour.