For those thinking about overclocking potential, its worth noting that OcUK have a couple of Ryzen prebuilt overclocked systems online:
https://www.overclockers.co.uk/pc-systems/gaming-pc/amd-cpu-gaming-pc
So we can assume these are safe overclock levels at least:
R7 1700 @ 3.8ghz
R7 1700X @ 4.0ghz
I would think they could probably be pushed a little more as the skylake/kabylake overclocked systems run at relatively conservative clocks as well compared to what most manual overclockers get out of them.
Reading between the lines from other posts by 8Pack for example, it looks like there is not a lot more headroom over these figures. Jury is out on the 1800X though, personally I expect around 4.5ghz overclocks on those, but again who knows at the moment.