The computer panel has a seperate FPS slider in the options, default for it is 40 FPS, even if you already set the game to 120 FPS.
And currently the base lights cost a lot of FPS, this will probably be optimized in a later update.
Makes sense.
It's not the computer that is lagging, though, its overall fps. Changing the computer FPS to 120 doesn't help.
Unfortunately I believe it is due to the base lights, I bought just two extra to light the area in front. Turning them off drastically improves FPS.