When you getting a double or more post procedure after a cold start, please have a look to the last QCode display. Which one is the last displayed code, overthere?

When it is Code 18 (Pre-Init phase of memory):

Help the UEFI BIOS to set memory settings:

Go after a successfully post into the bios and go to the memory timing settings page.
There you'll find all the settings applied automatically to your memory after training. Normally most of them or all of them have the setting AUTO.
So, noticed to every setting of timings what is the highest number of each RAM module and change for every setting from auto to that particular highest number of each ROW.

And save the bios settings, then restart. Now you can try a shutdown of the system, make the power go away and then make a cold boot.

When there's a cold double post again, try to set "proc ODT" to something between 40 Ohm and 80 Ohm. Have a try.
By my the best is 80 Ohms (Corsair Vegenace RAM (4*16GB)).