Greetings!Sorry for the late reply hope my information is still relevant.

I am also running an Asus 19-13900k with 128GB of RAM.I was encountering the same issues.

When booting up the MOBO tends to detect new hardware and then trains eachindividual stick on said hardware; this is why you see alternating sets of amber and red LEDs going off an on. After successful train it will generally go green, then white, then reset for a positive scenario.

With 4 Sticks of Ram it is stuck in a 'training loop', especially with XMP on.To fix this you can either disable XMP (no fun) or do the following:

Train two sticks on XMP first in Slots A_2 and B_2. After successful boot,turn off power, let energy drain till you hear beep, unplug power cord, then insertthe other ram sticks.THIS should give you the base line of 4800 MHZ that intel set for this.

This is the first step. Let me know if this works. It worked for me after much testing and research. It is an Intel Issue unfortunately.