Why OBS reduces fps significantly even if its not recording

[Danielb32]

As the title says, the FPS ingame reduces even if OBS is not recording anything which sounds odd at first glance.
I still get good fps but it is a big jump and I would like more fps for when the game gets fps hungry so any ideas why this happens and the solution?
When I use the game capture source it reduces fps but if I disable it then fps is fine, while if I use display capture then fps does not reduce(in both cases not recording just enabling or disabling in the scene). If I record then ofcourse I expect fps reduction but it does on top of this so it might be worth to have a look.

[Stan`]

I suppose OBS injects itself in a different way when running in game capture mode which slows down the game.