Question B550mh + R5 5600 OR A320m-k + R5 5600?

Welcome to the forums, newcomer!

What other brands do you have access to? Personally I wouldn't look into a board that has nothing to cool the VRM's near the CPU socket.

In retrospect, if you want pursue DDR4-3600Mhz then yes you migrate to B550 chipset/platform. The highest your chipset will allow is DDR4-3200Mhz.
 
Okay thank you so much, but do you think the cons of the B550mh outweigh the even more cons of using a 2017 mobo or do you think that's fine? I already have both motherboards in hand just gotta choose between using it or not using it.
 
Okay thank you so much, but do you think the cons of the B550mh outweigh the even more cons of using a 2017 mobo or do you think that's fine? I already have both motherboards in hand just gotta choose between using it or not using it.
I seriously doubt a 65W CPU can cause any heat throttling in any MB, A320 is even more likely to do that. With A320 you can expect RAM no more than 3000MHz (because of memory path architecture) if that, plus BIOS precludes any OC or even some precise adjustments. Their BIOS is just to small to provide as many options. No M.2 is serious minus for A320 so B550 is my recommendation.