Single channel or dual channel for ryzen 2600 build

Solution
Dual channel of course. High speed. 3200mhz or more. recommended 2 x 8gb matched kit.

Using Dual channel brings higher memory bandwitdh (theoretical) and some performance increases, application dependent.
in my case, single channel is all my notebook can do... lol, but, it's only for work. still, i can compile .NET stuff and run/debug just fine. good workhorse. oh, YES, the faster/better dual channel you can fit in the FASTER your gaming will be, maybe not at full settings on 1080, but still. If you still need faster, add a video card.