Hi there from Thailand,
I have read this thread last night after I decided to update my Asus Prime Z270-k bios to the most recent one. Before that I have experienced random error on post when I boot with cold start, but I could get it through after hitting F1 and quit without saving.
Not sure if my ram run at 3000Mhz (XMP enabled) or stock speed at that time since I haven't been regularly checking it.
However, last night my system show error on post again so I just gave it a try to update BIOS, but then my system just won't boot with XMP enable at all.
So just go through internet and found this thread and here I am.
I read all the comment in this thread and tried all the solutions, but none of them worked but after I came back and found the comment from "Daskeladden"
Luckily, I decided to give it a final chance if not successful, I will give up and use my RAM at stock speed (2133Mhz)
What I did is just simple, I enable XMP (Profile#1), go to advance mode, AI Tweaking and set DRam Speed to 2933, instead of using 3000.
Just like hitting the jackpot, my system just boot normally. Then I tried 3066, it also works for me
So I just stick with 3066.
Anyway, I haven not been testing my system or RAM that much since because it was too late night for me.
So I will come back if I get any error or Blue Screen when I use my PC in regular basis.
Update #1: just complete 1 pass on memtest86 with no error. Put all 4 sticks of 8GB (Corsair Vengeance LPX CMK16GX4M2B3000C15 3000Mhz) for the test at the same time. System boot normally. everything seems to be fine for me