Dual GPU, does it make sense?

DillTheKraut

Would Isadora benefit from dual GPU?

Despite the extra outputs, is there any performance benefits in using 2 Graphic cards?

best
Dill

DusX

There may be a performance gain if GPU heavy FX are being used (lots of FFGL, or GLSL, crazy amounts of mapping), or 4k footage is being used and mixed.
I would recommend against it unless you know you need it, because using the multiple GPUs requires unchecking the 'Shared OpenGL Resources' option in the Video Preferences. This means you must define the target stage at the beginning of a stream (in the Movie Player etc.. NOT at the Projector), AND you can NOT mix video stream that have different stage targets. Its a slightly more restrictive way to work, the Shared OpenGL Resources option really provides more freedom in building your projects.

If you wondering about things like playing HD or even 4K Hap files (since they use the GPU to decompress), these take surprisingly little GPU resources. @Fred has been using 4K Hap on windows, and may have something to add.

CitizenJoe

@dusx That's a very useful bit of information!

mark

@dillthekraut said:

Would Isadora benefit from dual GPU?

My understanding is that you have to write special code to activate the second GPU. I think (not 100% sure) that of the cards if for computing purposes only.

In this thread someone says the following:

"macOS hasn't been able to use both GPUs at once for graphics at once since the 2013 Mac Pro came out, so you aren't missing anything you had before."

But then someone says

"Not entirely true. MacOS just cannot use multiple GPU on single monitor's graphics (e.g. Crossfire), but it can use two GPU to drive two monitors graphics. I tested it myself. I can run Unigine Valley on one screen, and Unigine Heaven on another screen, and they powered by different GPU (as per the screen capture below)."

You'll also notice in this discussion that the cards in the MacPro are _underclocked_ because of heat problems. Not really what you want to hear when dropping so much money on a new machine.

Best Wishes,
Mark

DillTheKraut

Thanks @mark and @DusX,

if it's just about gaining outputs, would it be an option to have one very fast GPU for the main outs and a 'normal' one just for the Controllers and maybe a 'Preview Stage'?

mark

@dillthekraut said:

would it be an option to have one very fast GPU for the main outs and a 'normal' one just for the Controllers and maybe a 'Preview Stage'?

For texture sharing to work, it all has to be on the same card. So multiple GPUs really are problematic.

Best Wishes,
Mark

DillTheKraut

@mark,

thank you for clearing that out!
By the way, is the 'Stage sharing' function still on the Roadmap? (Span content over several outputs natively)

mark

@dillthekraut said:

By the way, is the 'Stage sharing' function still on the Roadmap?

Yes. But that's totally different than Texture Sharing, just to be clear.

DillTheKraut

@mark said:

@dillthekraut said:
By the way, is the 'Stage sharing' function still on the Roadmap?
Yes. But that's totally different than Texture Sharing, just to be clear.

Ok, great! But you want to tell me, this won't help me with the multiple GPU problem!? I think, I got that ;-).