Have you tried to manually input your memory settings.. get off the xmp profiles, it was killing my 1700 performance, after I manually input the memory timings my ryzen system worked better..
and flash your bios to the latest version..
He has 2 of 4 slots that don't even recognize the memory, and it is all identical ram. This has been a wide spread issue on Gigabyte Ryzen boards and his PC maker Cyber Power won't do anything about it as they don't support ram he bought and installed. To them it doesn't matter that slots 3 and 4 don't work only that what they sold works as is.
Problem solved (I think)
I had the same problem with my Aorus X-399 mobo. Was running 16 meg sticks 3600 mhz from Gskill in two slots. No problem.
Added two more and only saw 48 megs of ram and not the 64 that were installed. Got the ram replaced, same issue. Finally narrowed it down with the Gigabyte gal and we figured that one channel of ram was bad. In my case it was the D channel.
Gigabyte did the RMA but it's taking forever so I bought another mobo. Problem solved. Heard from Gigabyte who said there was "damage" although they said they were fixing it for free. Haven't got the original board back yet but all my slots read what's in them.
Now if I could only get windows 10 to stop crashing for no reason.....