When I last looked DDR4 ECC UDIMMs were 2x the price of non-ECC UDIMMs of the same capacity.
This feels very wrong when the only difference is one additional chip that in terms of material only should increase the BOM price about 12.5% (going from 8->9 memory chips).
It's 3-5 orders difference in the volume (and most of the time people buy high capacity modules) and ECC errors makes very obvious the need of replacing the module, while unregistered errors on non-ECC modules are just other 'something gone wrong' type and couldn't be diagnosed easily.
Also, onr of the primary markets for ECC UDIMMs are server/pro-workstation, thia alone.adds at least 10%
This feels very wrong when the only difference is one additional chip that in terms of material only should increase the BOM price about 12.5% (going from 8->9 memory chips).