Multiple dGPU for different workloads possible?

[Sonadow]

I am thinking of rebuilding my 11 year old desktop and am planning to install two GPUs: an Nvidia GT1030 and an AMD RX570.

The setup will be as follow:

• Both Nvidia card and AMD card will be on open drivers (because I want Wayland on both Plasma and Gnome Shell)
• Nvidia card will be used for display output to my monitor
• AMD card will be used for other tasks. Examples include video encoding in ffmpeg for my PS4 Facebook streams, or simply using it to run some other software instead of the Nvidia card on a need-to or want-to basis.

Can this be done?

[aht0]

AFAIK you cannot use secondary GPU for encoding video (incl streaming), you'd have to use the same card you have connected to the monitor. The only non-GPU hardware encoders you could use would be Intel's QuickSync (Intel non-Xeon CPU's iGPU have an encoder, better than Nvidia's nvenc at that) or dedicated HDMI-in capture card with an on-board hardware encoder. Not too sure what sort of PCIe HDMI capture cards you could use on Linux.

Elgato HD60 Pro for example has onboard encoder but it's only usable on Windows and with particular program Elgato is bundling it with.

[Sonadow]

AFAIK you cannot use secondary GPU for encoding video (incl streaming), you'd have to use the same card you have connected to the monitor. The only non-GPU hardware encoders you could use would be Intel's QuickSync (Intel non-Xeon CPU's iGPU have an encoder, better than Nvidia's nvenc at that) or dedicated HDMI-in capture card with an on-board hardware encoder. Not too sure what sort of PCIe HDMI capture cards you could use on Linux.

Elgato HD60 Pro for example has onboard encoder but it's only usable on Windows and with particular program Elgato is bundling it with.

I have an unbranded Chinese capture card bought from Taobao since last year. Works as a USB Video Class appliance and connects to the computer via USB3 , hence totally driverless.

Currently, I have been piping the output from the PS4 through a two-way active splitter; one feed goes to this appliance where ffmpeg is used to encode and downscale it to a 720p30 live stream to Facebook. Because Chromium and Firefox refuse to accept the feed from the device at native resolution; it automatically forces a VGA resolution. Can I use ffmpeg to encode the feed with the RX570 in this case?

And my processor is old enough that CPU encoding isn't ideal; even at superfast settings i can only output an average of 22 - 25 fps, which make for non-fluid videos.

Like i said, this is a plan for a complete desktop rebuild. Even if I cannot use the RX570, I have to upgrade the processor anyway. I hope to be able to use it for the next 10 years.

[aht0]

For streaming, best results (quality, resolution- and fps-wise) are generally achieved using separate dedicated PC for video encoding where CPU (at least i5, better if i7 (Haswell or newer) or one of the new 6C/12T+ Ryzen's) does the encoding and video gets piped in through capture card. It does not need dGPU at all.

[Sonadow]

For streaming, best results (quality, resolution- and fps-wise) are generally achieved using separate dedicated PC for video encoding where CPU (at least i5, better if i7 (Haswell or newer) or one of the new 6C/12T+ Ryzen's) does the encoding and video gets piped in through capture card. It does not need dGPU at all.

Even so, can I use the 2nd dGPU to do rendering? Like, say, in the form of DRI_PRIME=1 <some application> ?

[aht0]

You can try, it never worked for me.

[Sonadow]

You can try, it never worked for me.

Preferably will like to know before I start building my new desktop. Hardware is not cheap in my country.

[aht0]

Does your USB capture card register as an video encoder in software like OBS Studio (Windows, Linux and Mac versions exist)

[Sonadow]

Does your USB capture card register as an video encoder in software like OBS Studio (Windows, Linux and Mac versions exist)

It doesn't. OBS only recognizes the software x264 encoder.

I'm still keen on the dual dGPU setup though. Is there anything that the AMD card can be used for in the form of DRI_PRIME=1 <application> ?