All things considered, AMD has already announced that Zen 4 CPUs, either Ryzen or EPYC, will only feature support for DDR5 memory so this means that there’s no DDR4 IMC on the Zen 4 core. If the red team was to bring Zen 4 on the existing AM4 motherboards, then it would have to make special variants of the chip that house the necessary DDR4 IMC as AM4 is an all-DDR4 platform.
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