Krasser Gaming PC, - still low FPS during recording

I have a problem.

I have a pretty good gaming pc, specs:

RTX 2070, Ryzen 7 3700X, 16GB RAM, a small SSD and a larger HDD

At Streamlabs I have a 1080p recording with a 60,000 bit rate.

Recording is on NVENC (I've tried them all)

and rescaled to 720p

How can it be that as soon as I turn on Streamlabs OBS but especially when I "Rec." press, then my Fortnite felt dropping from 100fps to 30 Fps (at Fortnite)?

Game still says 120fps but that's never true.

I also play much worse because it is simply not fluid enough to react quickly enough (as is typical with first-person shooters)

Fortnite is installed on the C: hard drive

OBS too, but it saves the recording to disk D:

I overclocked my 60hz monitor to 100hz as long as I don't have a better one. (can the monitor be overwhelmed? Have 2 of a 100hz overclocked another 59hz for twitch chat - but otherwise the monitor shows safe 100fps without streamlabs)

Anyone tips?

This is due to fortnite itself, it was the same with my PC. If you try that in another game and swear that's gone

Sorry, but how do big streamers manage to start the game without having to suffer such a huge loss?

I used streamlabs myself. Could it be that there's something about the program?

But I also have to say that the streamers have pretty awesome pc's ^^

Streamers take a game capture card and stream via a second PC system (mostly)

Well, streaming costs performance which must come from somewhere

Can you imagine?

So the only thing I think it can be is that the driver does not fit. I also read into the whole artery and for me it continued at Fortine and stream at 144fps (game attracted to it). At the time, however, I also tried OBS.

Specs:

i7 8700k 5.0 GHZ

Msi Gtx 1080

16Gb Ddr4 3666Mhz

Msi z370

512gb SSD

2TB HDD

Hm yes you are right, I ask my 8 cores and 16 threads where the performance should come from

Games pull in as much as they can and when competition comes they react just like that. Streaming is something that runs through the rendering. That's just how it is. You could even better put 2 pc next to it.

So seriously said that my PC is not enough to record gameplay? If that's true, money spent violently in vain.