Hi, I would like to say that my previous RAM was 4gb 3200 MHZ DDR4, after I face with some problem I decided to upgrade my RAM and I did. I changed with 2 8gb with 2666 MHZ DDR. but still I experience glitch while watching videos and seeing the interruption while moving the mouse. 

Could you please help me to solve this issues, do I have to turn on to 3200 MHZ ram or? different problem?