Although it does seem some B350 boards are achieving the same, if not high clocks than some X boards. It seems very down to the CPU rather than the motherboard. This maybe different with the Zen+,
I had more success with the crosshair than the tomahawk. My chips is admittedly a poor clocker [email protected] but I couldnt even get stable on the b350 at 3.8. In my experience and from what I've read the x370 can get the most out of them - especially poor clockers. Think back to the fx8350 and only 990fx could get the best from them. This could end up being the same for zen+ speculation of course but its a possibility.