As others said GPUs have failsafe mechanisms and after a certain temp is reached they will throttle or stop working with fans blowing at %100. You're probably fine.
My old GPU had coil whine too especially when fps was too high. Turning on v-sync or locking framerate usually helped a lot, I know it's not a permanent solution but you can give it a try.
Recent patch really affected performance negatively especially in cities with players with shiny mtx on them. My suggestion would be turning on v-sync if you haven't could effect the performance but would decrease the load on your gpu.