JEDEC specifications for DDR4 top out at DDR4-3200, and anything beyond that is vendor overclocking with whatever settings that particular vendor deems is suita

JEDEC specifications for DDR4 top out at DDR4-3200, and anything beyond that is vendor overclocking with whatever settings that particular vendor deems is suitable. While there's nothing technically preventing vendors from factory-overclocking ECC memory the same way, ECC's (perceived) main audience is reliability-critical systems, and so it doesn't make sense for vendors to market a feature that their target audience wouldn't appreciate. What you can do is get two 32 GB DDR4-3200 memory modules (example: https://www.crucial.com/memory/server-ddr4/mta18asf4g72az-3g2b1 https://www.crucial.com/memory/server-ddr4/mta18asf4g72az-3g...), and then overclock them yourself to 3600 MT/s. As with any overclock, your results may vary, but that's also the case with factory overclocking as well.