[LargoLasskhyfv]

Interesting. I guess the DIMMs came blank, without heat sink/spreader on the chips, since ECC and therefore "non-gaming"? In that case i'd try some thin aftermarket clip-on. Nothing hilarious like "HyperRacerMegaBlingMarkVII" would come with. To see if the ECC-errors occur because of running out of specification frequency wise in general, or if they just occur because of running at too high temperature because running at a too high frequency (and maybe voltage) without cooling. Because vendor didn't plan/produce/verify for that use-case. So I'd verify that, and enjoy in case of the latter.