The minimum required CPU is the i5 6600K. Your low GPU usage shows that you are experiencing CPU bottlenecking. Your GPU meets the recommended specs though.
The odd thing is though that the recommended CPU for AMD is the Ryzen 3 1300X quadcore CPU which looks to have very similar performance to the i5 6600. I cannot think of any reason why the 1300X would meet the recommended requirements but the i5 6600 would be below the minimum requirements as the only real difference that I see is that the 1300X officially supports faster DDR4 memory and has more L3 cache.