that ryzen system is pretty badly gimped... it relies heavily on ram performance... and with one stick of ddr4 you've just Gilloolied that chip.
I would think that is the reason you're not getting the numbers you see in the reviews - with dual channel, some TRFC tweaking, you should be putting up scores much faster than the old Penryn system.
Also gaming performance relies heavily on ram throughput. Gaming with one stick in on an amd system will choke it. You're going to get stutters like crazy.
I've never built with a platform this sensitive to ram and also one that requires as much tweaking (common ryzen complaint). You may want to go dual channel and make sure to tweak the ram up, you're going to see some much better numbers.