Hello Josh,
No, you don't have to set anything. The only important thing is the dual channel (if you look at the RAM slots, it is always 1+3 and 2+4 with 4 slots).
But since you buy 2 additional slots, this is done automatically anyway, you don't have to set anything unless you want to overclock the RAM (voltage etc.).
hey, i have the 2x 16GB of these sticks running on a MSI B450 Tomahawk @3333Mhz. my cpu is a 2700X, so i'm pretty sure it will work with a 3700x as well. the Tomahawk board is a good choice, it has enough power for a 3900x.
I hope I am giving the installation height correctly, I have measured both times.
from the slot to the edge of the RAM= 30mm
from the bottom (MB) to the edge RAM= 37mm
Servus.
I would choose 2 slots with 32 GB each.
Then you still have the option to upgrade to 128 GB with an additional 2 x 32 GB.
Greetings from Bavaria
What do you think you can achieve with 4000 and co. if your CPU is only designed for up to 2666 Mhz? It won't be any more, you can put whatever you want into it.