How to make friends 2666 MHz and 2400 MHz RAM on asrock b450 pro?

Question

Iron

Hey!
They gave me 2 hyper fury sticks for 8 GB 2400 MHz each.
My horse already has 2 hyper fury sticks of 4 GB 2666 MHz each.
I always thought that if you put a RAM with a lower hertz, then all the memory will work at the lowest available frequency, but ... it wasn’t there. It sluggishly waves coolers and goes into reboot, if you just load it with 4 bars.
All slots are in order, they see any bar, and these friends work perfectly in pairs of 8 and 4 GB, respectively.
Asrock b450 pro mother with latest bios.
What I tried:
Manually lowered the frequencies of the 4 GB sticks from 2666 to 2400, set the timings to 15-15-15 and added 8 GB of beauties.
It didn't work. The computer genially moves the coolers and goes into reboot.
Moreover, once it turned out to make friends with one "lowered" 4 GB bar with one 8 GB one, but the further addition of the next 8 GB bar broke everything ...
So far I have only written to huper X support, who just advised me to tweak the timings.
PS. I would be happy with any slippers, because when I first assembled the computer I could not understand why it was not working. And I just forgot to connect the power to the processor.

Answer 1

What is memory? Write accurate markings. In practice, there were cases when single rank and dual rank memory did not work together, only one type. Manual page 28(23)