SgtScream :
That is the problem. You are running one memory stick so the board cannot operate in dual channel.
I wouldn't say that IS the problem. I would say it's definitely a contributor to the problem ALONG with the fact that aside from not having dual channel they are also running slow memory. I absolutely agree that if they were running 2933mhz or higher memory that was ALSO in dual channel configuration, they probably wouldn't be having this problem. Installing a second, IDENTICAL part number module, MIGHT help the issue but it is STILL going to suffer from being low speed memory on a platform that clearly shows poor performance with low speed memory.
I also wouldn't say AT LEAST 3200mhz, I'd say 3000-3200mhz, because the fact is that very few users are able to get memory faster than 3200mhz to run on Ryzen platforms (At least, not at speeds higher than 3200mhz. You can certainly get a 3600mhz module to run AT 3200mhz, if the module is favored by the chipset to begin with or if you are willing to do a fair amount of fiddling with the timings and voltage in the bios) and those that are able to are generally people that are using much more expensive modules with Samsung B-die ICs (Memory chips). It's highly doubtful that you will get a Hynix M die or Samsung D or E die module that is faster than 3200mhz, to run on any Ryzen consumer platform.