... Well technically there would be some, but it's not even close to noticeable compared to the normal streaming setup, which means encoding using your CPU or GPU which you are already using for your game.
My old setup consists of a single GPU, single CPU and, encoding using NVENC or X246 (CPU). The problem with this setup is, even with a beast of a CPU or GPU, you can feel a sort of sluggishness or sponginess in games, even thought your frames are high - similar to the feeling to when you play shooters with v-sync on (input lag).
In certain games, this becomes very noticeable, like most shooters or games which in general requires fast and precise mouse movements.
Now, dual-pc streaming seems to be the trend, but it brings with it a whole new set of issues, with price being one of the big once. But what if I told you there is another way, you could get close to that 2 pc setup QOL without it requiring you to build another computer and for just a fraction of the price?
Dual-GPU setup, but not 2x monster expensive cards either.
But, you need to use a card from both the red team (AMD) and the green team (Nvidia). You might be able to do it with two cards from the same team, but I will go into why I don't suggest it and why I think it might not work.
My new setup looks like this: 1x RX 580 from AMD which I will be using for encoding, and my 1080 TI which I use for my games. The reason I went with this setup is because I have an 1080 TI already, and AMD cards are cheaper to get a hold of (got the RX 580 for about ~110 GBP/~150 UDS), just make sure you get one of the RX 500 series cards or otherwise newer cards which have AMD's "new" Advanced Media Framework support. I don't know if any of the old once support it or if so, how far back, hence my recommendation for 5xx series.
You probably don't need the RX 580, but since I dual boot into a hackintosh, I wanted the extra performance headroom while I work.
Just leave the card in your machine, don't plugin anything into this card (monitors, capture cards etc), you purely have it there for encoding, windows (10) is smart enough to know which GPU to use for your games etc , as it would be the one you have your monitor(s) plugged into.
To use your AMD card for encoding is dead-easy, you just specify you want to use AMD Advanced Media Framework), in the dropdown called "View Mode" you can set it to advanced to really open up for a lot of tweaking to your encoding settings.
I was able to stream Escape From Tarkov without dropping any noticeable frames, and without the game feeling sluggish or input-laggy like my old setup.
Here is some of the usage details while in-game:
All in all, this has made my life so much easier and makes me want to stream more, as it does not/hardly impact my gaming experience. Of cause, your milage might vary based on your own hardware etc, but for me this worked out like a charm and couldn't have been any easier.
Edit: On a side note, let me know if you end up doing something like this. I am very curious how it turns out for you. You can find me via my contact page or on librt.tv/sirmre when I am live.
Additionally, the CPU/GPU usage is fairly normal if you use your GPU for encoding, the difference I felt was if you encode on the same GPU as your game is rendered on, it feels like you have input lag.