Low GPU usage and low FPS RX 480

Good day!

I've got an issue with RX480 - low GPU usage(100%-0% spikes) and low FPS in games( Tomb Rider 2013, ROTB, Witcher 3 etc.). This issue is not depending of quality settings,and on all settings i've got about the same low FPS.

CPU: Xeon 1241 v3, RAM  2x8GB 1600, WIN7x64, MB ASUS H97M-E, HD Samsung 850 EVO 240gb, WD Black 2TB 64Mb cache. GPU Saphire RX480 NItro+ 4GB.

Tried to OC my ram,(1600 -> 1866) but, unfortunately this didn't solve the problem.

Seemed like VSYNC is turned on, but i've checked several times, it's off.

DxDiag, screenshots and videos on the link : https://drive.google.com/drive/folders/0BxsqbitpjHGrUlhLd2I2UHREMlU?usp=sharing

Thank you in advance for your help!

Best Regards, Alexander.


P.S. Doom@Vulkan  runs pretty well, 120-140fps on 1920x1080.