DDR5 (on-die ECC) vs DDR5 ECC (EUDIMM)

[Maor]

I have currently DDR4 ECC EUDIMMS in my system and never noticed ECC kicking in in my logs.

What is you opinion on next gen Ryzen with DDR5?

 

Is the on-die ECC enough to be safe from bitrot and thus any DDR5 is fine home server or is the cost of full blown ECC worth it?

[ChatNoir]

From what I understood, the on-die ECC that is standard on DDR5 is not proper ECC, just a way for manufacturers to overcome limitations of this new generation.

Proper ECC should be paired with ECC checks from the memory controller (on the CPU nowadays).

 

But I cannot find the source I read/watched about this.

[Maor]

I am looking into this https://users.ece.cmu.edu/~omutlu/pub/memory-errors-at-facebook_dsn15.pdf
It appears that bank errors are quite common and I am not sure, that those can be corrected by on-die ECC.

[JorgeB]

One of the problems with on-die ECC is that it won't report a problem if there's is one, while normal ECC does.