What are the temps? It will start to throttle around 75c and it's recommended not to exceed or really go near the limit of 95c. You're h115i should be more than enough for Ryzen, what chassis are you using? You may benefit from additional intake and exhaust fans. Also you could add a fan to huff on the board vrm heat sink to replace airflow lost from an air cooler when utilising an aio closed loop. What mobo?
Pump rpm in bios? Hopefully it's still spinning. Some aio's don't really give any external indication of whether the pump is spinning as they are silent and don't always make a vibration so the only way to tell is the rpm reported in the bios. Aside from temps. being unusually warm. Also check to ensure that the cooler is correctly fitted with good contact to the cpu with thermal paste applied.
PWM fans, all running at a good speed?