Does a Capture Card give you more FPS?

So if I bought a capture card and streamed it, I would have as much FPS as if I was streaming with an emulator. So that depends on my laptop or the recording or even the stream will still remain as fluid as it is on the now e.g. On the switch is running?

The capture card is external and so the laptop consumes no extra power to record. Yes, that's why it basically brings more fps

The card itself does not bring any extra FPS. However, she relieves the pc and so he has resources for games.