Lag spike, GPU and FPS DROP empty scene

Hi I’m just starting learning Unreal Engine and I got a really frustrating problem.

On every scene, even empty, my FPS are constantly dropping from 100 to 15 like every 10 seconds.
My Gpu is switching between 90% (no lag) and 8% (lag)
The same thing is happening with CPU (22% no lag - 5% lag)



CPU : I9 12900KM
GPU : RTX 3090

During the lag spike all the computer is lagging.
I can’t learn correctly I can’t even sculpt a landscape with those insanes lags.
Can someone help me ?

Thank you !