I need information and advise, please help to define, is it problem or not. So, My processor model is Intel i5-9400F on Z390 A Pro motherboard. When I look the CPU speed in Task Manager, It is always between 3.9 and 4.0 GHz. Even I open the chrome and watch the movie. I do not know, is it the normal case or not.
This is what I would expect to see. Your processor's Max. Turbo Boost is 4.1GHz and this is only going to be achievable when just a single core is active and sufficient thermal headroom is available.