z390 phantom gaming 4 RAM question

Try each stick individually in slot A2 and make sure they are all working. If they
all work fine then populate slots A2 and B2 and try with that using different combinations.
If all the modules work in dual channel like that then populate all the slots and
try.

Mixing and matching RAM brands and models can cause issues, particularly when 4
modules are in use. More RAM modules = more chance of incompatibility.

If you are using 2 kits of 2 then try them in different combinations, that can
make a difference and may allow you to POST. Failing that, go into the BIOS with
a single stick installed and set the RAM speed manually to 2133 and then try all
4 modules again.

If that doesn't work you may be out of luck.

Good luck

Try clearing CMOS. That should get you back to system defaults and sort out the
issue with entering the BIOS.

As a general rule, always clear CMOS before adding new RAM, it will force the system
to retrain the RAM and might make your 4 modules work.

I read this in the manual:

"It is unable to activate Dual Channel Memory Technology with only one or three
memory module installed".

does that mean one or three memory modules installed wont' work at all or it will work but just not in dual channel mode?