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Does Adding Screens Use More VRAM?

Posted: Sat Jul 21, 2018 01:43
by Arvol
Hey Guys,
I have a large composition 14,440 X 4,000 and I'm going to be breaking this up and sending it out multiple outputs on my GPU.

Right now just using a virtual output i'm sitting at 75% VRAM usage.
If I connect and output this to 4 outputs, will this add any additional strain to the system?

Setup is 2 GPU's GPU1 is UI, GPU2 is 4 output's (in sync via Quadro sync)

Thanks

Re: Does Adding Screens Use More VRAM?

Posted: Mon Jul 23, 2018 10:39
by Joris
There is some optimisation that a virtual screen doesn't actually do any rendering until its output is being used for something. It's textures should already be allocated, so to answer your specific question, no, going from virtual to actual shouldn't use more VRAM. It will use up more GPU cycles though.

Then again, that's the instructions we give. A GPU also does loads of optimisation of its own that we can't control. For instance, it may decide to offload a texture to RAM if it's not been in use for some time.

Keep in mind that every texture going out the second GPU has to travel down the PCIe bus of the primary GPU and up the other, so you'll want to first use the ports on the primary as much as possible.

Re: Does Adding Screens Use More VRAM?

Posted: Mon Jul 23, 2018 16:10
by Arvol
I see. Thanks for the info Joris :)

With 4 outputs needing to be in sync, and the UI screen's GPU doing the rendering, What would you suggest? Anything I could do differently?

I need to keep the 4 outputting screens on the same GPU (Quadro series, so the output's are in sync and there is no tearing).

Re: Does Adding Screens Use More VRAM?

Posted: Tue Jul 24, 2018 00:05
by cvanhoose
Arvol wrote: Mon Jul 23, 2018 16:10 I see. Thanks for the info Joris :)

With 4 outputs needing to be in sync, and the UI screen's GPU doing the rendering, What would you suggest? Anything I could do differently?

I need to keep the 4 outputting screens on the same GPU (Quadro series, so the output's are in sync and there is no tearing).
I recommend a Datapath fx4. 1 output for your GUI and 1 output to the fx4. Not sure what your main card is, but with 2x 8k outputs and 1x 4K GUI, I am only utilizing 20-30 percent of a 1080ti card. 9 layers.

Re: Does Adding Screens Use More VRAM?

Posted: Tue Jul 24, 2018 03:32
by Oaktown
Arvol, you mentioned a 14,440 X 4,000 composition but what do you need to ouptut?

I'm with cvanhoose on this one and with one 1080ti driving (1) GUI and (3) Datapath FX4 using short DP cables (and possibly more FX4 units using the pass through DP), you can drive a very large composition.

Considering each FX4 can do 2160p/60 (and even 3840x2400/60), you can get creative and play with the refresh rate to make it work for you. For instance you could split your comp in thirds and do (3) 4814x4000/30.

Re: Does Adding Screens Use More VRAM?

Posted: Sat Oct 20, 2018 22:08
by e23415
cvanhoose wrote: Tue Jul 24, 2018 00:05
Arvol wrote: Mon Jul 23, 2018 16:10 I see. Thanks for the info Joris :)

With 4 outputs needing to be in sync, and the UI screen's GPU doing the rendering, What would you suggest? Anything I could do differently?

I need to keep the 4 outputting screens on the same GPU (Quadro series, so the output's are in sync and there is no tearing).
I recommend a Datapath fx4. 1 output for your GUI and 1 output to the fx4. Not sure what your main card is, but with 2x 8k outputs and 1x 4K GUI, I am only utilizing 20-30 percent of a 1080ti card. 9 layers.
can you share you rig setup? from a single 1080TI this is amazing! 2x8K + 4k GUI!