Dual PC streaming setup - huge performance loss on main gaming PC

[walk]

I have a 9800x3D and a 3090 on my main gaming PC. I have a capture card, which then goes to a seperate PC for streaming.

The issue I'm having is that I'm experiencing HUGE performance drops on my main PC, no matter what I'm doing. My primary game is The Finals, without OBS up, I play at approx 280-300 FPS. With OBS up, it drops down to 150-240. The method I tried for this was having windows treat my capture card as an additional display, then using OBS fullscreen project onto the it, a method I found online that many users claimed was the best way to do it and would result in no performance loss.

I also tried a different method, which was duplicating the screen (and not having OBS on the gaming PC at all), but this had the exact same issue - performance would drop down to 150-200ish FPS while the screen was mirrored.

How do I solve this? The entire point of a 2 PC streaming setup is that the primary PC is not impacted performance wise, but I'm out here losing almost 50% of my FPS no matter which method I'm using to get the video over to the other PC? Does anyone know how to set this up correctly?
My main monitor is a 1440p/480hz, but I'm running it at 1080p/360hz (since The Finals is extremely GPU heavy, I need to use 1080p to get good FPS).

There's no OBS log in this case, because that only generates for a stream/recording, and since I'm only trying to use OBS as a projector, there isn't any log generated.

 

[qhobbes]

Get an HDMI duplicator, connect source end to your gaming PC. Duplicate HDMI to your gaming monitor and capture device, which should be connected to your capture PC. Run OBS on capture PC.

 

[koala]

If you want to directly capture your gaming PC monitor, your capture device needs to support the fps you output to the monitor (360 Hz/fps in your case). A HDMI duplicator must support this as well, as far as I know.

You tried capturing your game with OBS on the gaming PC, then projecting this a fullscreen projector to the capture device. Since it didn't work out as you expected, I guess 280-300 fps might be simply too much for this: First capture, then output the whole video data to the GPU again. To what fps did you set the capturing OBS running on the gaming PC? Try to set it to 300 fps in Settings > Video and see what happens. Then set it to 60 fps (probably your streaming fps) and see what happens. If used as projector, set the capture device to 60 Hz/fps. May be one of the variants work for you.

But if you want really zero impact to your gaming PC, you have to directly capture your gaming PC with a capture device supporting that high fps (360). As far as I know, there are not many, if any.