I have mac pro 5,1 running Monterey with the latest OCLP (opencore legacy patcher) and I have been suffering this problem for long time. In many posts, it is assumed to be acceptable, and was advised to do nothing. There has been a common issue for Vega cards on classical Mac (4,1/5,1) running BigSur/Monterey: the fan is not spinning fast enough on idle, leading to an unreasonable high temperature (~ 75'C).
