arnoldle9 :
Corsair Vengeance LPX 16GB (2x 8GB) DDR4 3000MHz paired with the motherboard and a ryzen 2600. also is 3000mhz viable with ryzen
I'm not sure the motherboard QVL will be all that helpful...but maybe Asrock has updated theirs since the B350 boards released in early 2017. Since you're going to be running a 2600 CPU you'll have the advantage that at least it is specified to support 2933 memory.
I assume you'll get a board with a 'Ryzen 2000 ready BIOS' already in place (you'd better with a 2600 in there) but even so update to the latest BIOS as soon as possible. Reason being: they've made regular and steady improvements in memory support with each BIOS/AGESA release. With the latest AGESA in place I believe one could say 3000 is...