GPU RTX4090 v.s. RTX 3090

you recommend to use 2xRTX3090 graphics cards for Omniverse Create XR. Is it because of SLI over the NVLink? Does it make sense to use 1xRTX4090 plus 1xRTX3090(which we already have)? And in which way can it be usefull. Can one card compute PhysX while the other is computing real-time rendering? Or is there any other way to utilize this GPUs combination. What will be the benefit?

Thank you for any useful info…

Hi Jiri,
We do not recommend using SLI with Create or Create XR. Both software apps will correctly find, use and take advantage of your multiple GPUs without needing to physically connect them in SLI.

You can use NVLINK if you wish but this is for Quadro cards only. Like 2 x Quadro A6000 cards.

As a good general rule you want to always have your fastest card as your primary, so your applications run faster.

Create and Create XR will use all available GPU power very well, so if you upgraded to one 4090, and one 3090, in theory, that would be a big speed advantage over 2 x 3090s. HOWEVER, as yet we have not tested a mix of a 4090 with a 3090 for stability.

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Have you had a chance to test 4090+3090? Thinking of adding 4090 just for Create - will it utilize all 48Gb of VRAM if mixed with 3090?


I haven’t had a chance to install both of them. They don’t physically fit in the case using the motherboard that I have. I’m searching for water cooling system to be able to install both. Water blocks are thinner that heat-sinks.

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Just to clarify on the use of VRAM and Create. Create cannot “combine” two seperate cards VRAM into one pool. Create, like most GPU software can only use the amount of VRAM on the smallest card you wish to use. So if you had a 24GB and an 8GB card, Create can only use a maximum of 8GB. All cards in use are bound by the smallest amount. So with a 24GB 3090 and a 24GB 4090, it would only use a maximum of 24GB.

And as a follow up to that, in general it is not a good idea to mix cards. Ideally you want the same card repeated. Certainly not different memory amounts or GPU classes. We do not gaurantee support and stability with mixing a 3090 with a 4090 as they are very different cards.

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I am using Kaolin and a single 4090 on Linux, but it looks unstable. it is constantly flickering/vibrating
Untitled_ Jan 9, 2023 10_42 AM

In Create some buttons disappear and reappear and it takes a while to open.

giving this message.

Should I get a second 4090 or move to the A6000?

Thank you for clarification! Just to make sure - Omniverse won’t utilize 48Gb VRAM available if used with 2x 3090 in NVLink, only 24Gb still?

Yes correct. NVLINK is not supported by Create or by the Geforce series. So even with two cards you will only get a maximum of 24GB. But ofcourse with double the cards, you get double the speed of rendering.

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Just an update that I’m currently testing this setup with TRX40 system, 3090 and 4090. And, for example, on my scene the rendering time is dropped from 40 sec/frame (on 4090 only) to 21sec/frame in Path-Trace mode.

Since (as far as I understood) you still have to add “–/renderer/multiGpu/enabled=true” command in 2022.3.1 argument to the Create’s .bat file shortcut for multi GPU support, the command line reads: “Disabling DLSS Frame Generation for at least one view due to incompatible render outputs” - so, i guess, the DLSS stuff does not quite work with this setup.

Yes that makes a lot of sense on the DLSS support. That is difficult across two different cards. Multi-GPU should be ON by default. You should not have to add a command line. Can you try without the extra command line and let me know.

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Without the command line only 4090 is detected in Heads Up Display → Device Memory.

If the “–/renderer/multiGpu/enabled=true” command added to the omni.create.bat shortcut, then the Heads Up Display and the cmd window that pops up recognize both devices.

Task manager also reads no 3090 utilization without the command line, but does with it. Also MultiGPU options in PathTrace render settings are missing without the command line.

Actually, I have just found out that in fact you are correct to add the manual code. For two or more cards are the same specs, the OV launcher will auto detect multi GPU. However, when you have two different cards, and in your case, two different classes, it will not auto detect. You can turn it on and off manually inside Create, in the Preferences.

So for now, yes keep the .bat code in.

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