Question / Help Using a second video card with OBS 23.2.1

[campcreekdude]

I can't find the location to select a second video card.

My setup is that I want the HD 7970 to record and I want to game on my GTX 1080 Ti

This would be a cool setup.

Thanks.

05:31:33.765: Initializing D3D11...
05:31:33.765: Available Video Adapters:
05:31:33.768: Adapter 0: NVIDIA GeForce GTX 1080 Ti
05:31:33.768: Dedicated VRAM: 3077570560
05:31:33.768: Shared VRAM: 4267300864
05:31:33.768: output 0: pos={0, 0}, size={2560, 1440}, attached=true
05:31:33.768: Adapter 1: AMD Radeon R9 200 / HD 7900 Series
05:31:33.768: Dedicated VRAM: 3200368640
05:31:33.768: Shared VRAM: 4267300864
05:31:33.769: Loading up D3D11 on adapter NVIDIA GeForce GTX 1080 Ti (0)
05:31:33.822: D3D11 loaded successfully, feature level used: 45056


I want to load on
05:31:33.768: Adapter 1: AMD Radeon R9 200 / HD 7900 Series


Did the setting move away?

 

[koala]

Unfortunately, you will not be able to increase your performance with 2 video cards.

You make the best use of PC resources with a Nvidia GPU if the game and OBS both run on the same Nvdia GPU and you encode with nvenc (new).

This way, data movement is minimized and data processing is done in the most efficient way. All data handling and processing is done within the same GPU. OBS captures the game frames from the GPU, and the same buffer that is used for frame data is used by OBS for compositing the video. The final video is rendered into a new frame buffer and is sent directly to the new nvenc encoder within the GPU. Required to downloaded to CPU memory is only the small encoded video frames of the final video.
Using the GPU for all this is best, because the GPU is explicitly made for this kind of data processing. Nvenc is even a dedicated circuit on the GPU, so using it doesn't take up any GPU rendering or computing resources. Well, actually it is able to use a bit of it for quality reasons, but if you use the "performance" preset and deactivate look-ahead and Pseudo-visual tuning, there are no computing resources of the GPU used.

If you intend to split data processing between 2 GPUs, raw (big) data has to be downloaded from one GPU and uploaded to the other GPU. This hogs down the pci-express bus as well as the GPUs themselves. You gain nothing by doing this. Instead, you have a much heavier burden on your whole system.

tl;dr:
physically remove the AMD GPU to give the Nvidia GPU the complete x16 pci-express bandwidth. Use the nvenc (new) encoder.

 

[campcreekdude]

I guess it works... just needed to use simple settings and choose AMD hardware encoder.
In advanced it seemed not to work. I guess I am a simple computer man.

 

[Narcogen]

There is no need to do this. Your 1080 can run the game and record it in better quality than the 7900 without any additional load whatsoever; the encoder chip is separate, dedicated hardware. You're degrading the quality of your recordings for no benefit.

Koala is right. You will get better performance by removing the AMD card altogether.

 

[campcreekdude]

Yea I am sacrificing some PCIE lanes bandwidth. I am running 8x , and 8x. Negligible difference at 16 x
7970 is at 80% useage when recording and the 1080 Ti is at 20% useage in a low requirement/highly optimized game.
I imagine if push comes to shove in the future this setup will be worth-while.

 

[koala]

The AMD hardware encoder is vastly inferior compared to nvenc on the 1080. You also sacrifice much quality.

Sometimes, it might look cool to reuse old hardware and shove as much in the computer as possible, but actually, it's not helping. A clean and as simple as possible hardware setup with the minimum amount of required hardware components is the most stable and best performing system.

 

[campcreekdude]

I haven't looked at the encoder settings but it seemed like an alright file to me.
OBS is definitely better than game shadow. I prefer Radeon Re-Live to Nvidia Game Shadow or whatever their recording is.