Why is my CPU massively underperforming?

[Mohdhar]

UserBenchmarks: Game 28%, Desk 24%, Work 19%
CPU: Intel Core i5-6600 - 18.9%
GPU: AMD R9 390 - 55.7%
SSD: Samsung 850 Evo 500GB - 70.9%
RAM: G.SKILL Ripjaws V DDR4 2133 C15 2x8GB - 36.9%
MBD: Asus Z170-A

Just ran a test at userbenchmark.com after i have been getting way less than ideal fps for the specs i have. (I only get 90 fps on league with dips down to 20 fps on 1080p) If my temps are fine, why would this happen??

 

[GhislainG]

Is the Windows power profile set to high-performance? You verified the CPU runs at its rated frequency during the benchmark?