Ryzen 5 1600 stuck at 1550 mhz

I bought a Ryzen 5 1600 new and a msi x370 sli plus used, I tried overclocking the r5 1600 but anytime i try to do an overclock i look in Cam software and it shows 1550 mhz and i test my processor in Cinebench and it gets an extremely low score like 400's. I have downloaded all the latest drivers and I have the same issue no matter what. I have to voltage set at 1.3 and it still doesnt want to work, it seems to down clock it to 1.5 each time i do it. Then when i take the overclock out and test it in cinebench i see that my score goes back to the 1100's. My processor is cooled by the h100i gtx. Please help if you could!