Is Dynamic Global Illumination supposed to kill my frame by 120fps?

Hello, rather simple question for clarity.  My PC setup is AMD, a Radeon RX 7900 XT gpu with a Ryzen 7800x3D cpu. I can run the game on all ultra with absolutely no problem. However, when I have the Global Illumination set to Dynamic, my frames go from ~200 to ~80 compared to when it's set to Static. Is this normal?

Hoping to gain insight from other players.