Hi, A customer just sent me the parts for two machines - all purchased at OC I don't want to overclock anything (yet) The relevant bits: i7 8086K S-spec @4000MHz Gigabyte Aorus Ultimate Gaming z370 Corsair Vengeance DOMINATOR Platinum 2x16GB @3466 I built the first machine last night and have not slept since My only problem - The RAM will not run anywhere but 2133. I set it up, go through the whole "The system has experienced a boot failure ... ", set it up and then boot override so it goes straight to the OS (which, I mistakenly believed 'forced' my custom settings but, it seems, just 'restores' the basic speed before booting) where AIDA tells me NO! - 2133!!!! Stupid human. I have followed guides and searched forums but this is the first place for me to display my failure/ignorance. Yes. I reset to defaults. Every time I failed. Yes. I cleared the CMOS. Regularly. Yes I tried the other pair of slots. Yes I tried the other pair of sticks. Yes. I tried the other pair of sticks in both pairs of slots. Permutate any 2 from the above and I have tried it Thanks in advance.