Asus Crosshair VI Hero.
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What I found peculiar is that the CH6 pumps all that power to the 1700X. I never saw it delivering less than 1.41v to it even at stock speed of 3400 while idle. And never managed to OC the poor sod.
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Personal experience notes. Second Asus board I bought ever, (previous 11y ago and returned it straight away also) and only had issues with those two boards over 22 years period. Having used ECS, Abit (NF), Via (numerous of the KT series), MSI (X79), Gigabyte (990FX), Foxconn and Asrock (Z170) without problems from the first boot and vicious tinckering. (VIA KT series was sorting their jumpers for heaven sake).
Especially the Gigabyte I owned and sold, is still going strong with an overclocked 1090T 7 years now without issue.
Anyhow, maybe next year with the Zen+ will be luckier. Both CPU and Motherboard are packed and RMA process already started. Going to drop them off to DPD point for collection.