I am fine with downclocking the RAM; my X870E board (ProArt) should be fine running ECC, I only use 9800X3D to have a single CCD (maybe upgraded later to EPYC 4585PX) and together have RTX 6000 Pro and 2x NVLinked A6000 in PCIe slots, with two M.2 SSDs. Power supply follows the latest specs as well. This build was meant to be a light-weight Threadripper replacement and ECC is a must for my use cases.