Ryzen start throttling at 85°, the boost of the 2700X range from -5°C for 4350 full core under heavy load and slowing decreasing the boost until 85°C, with a sweet spot around 50° to 60° to maintain the boost around 4150MHz, then after the curve is steeper to 85° when it reaches the base clock (3.7GHz), and so then it start reduce the multiplier below the base clock