Hello everyone. I'm having the same issue with CPU speeds droping down to 400. But I think, it is not a CPU issue, it's got to do with the Nvidia GPU. I was playing around with Unigine Heaven and monitoring the temps and speed. Every time the GPU hits around 72 degree, the CPU drops to 400 Mhz. After playing with temp limit in Ryzen Controller, i've got CPU temperatures as low as 70 degrees in Heaven, but still drops to 400 Mhz, when the GPU temps were above 70 degrees. It seems like the GPU is making this drops. I don't know if it is a BIOS or Windows 10 problem.