Is this accurate? It’s unfortunate that one even needs to come here to ask this question but there’s zero mention from official channels available and for people and teams who invested tens of thousands in rigs specifically meant to maximize Unreal rendering performance, “shadow-killing” such an integral feature with zero explanation as to why is an incredibly ■■■■■■ thing to do to a community if it’s true.
Is this “person” an AI bot or what? If so it needs better training being it’s posting responses that have nothing to do with anything mentioned for some reason.
Cmon dudes; Epic. Own up. You mention the smallest most insignificant change in code in every patch but zero mention of “removed the multi-GPU support we just added last year” in the 5.4 notes or ANYWHERE on the internet. Did you think people who took out loans to purpose-build for rendering in your engine just “wouldn’t notice” a 50% reduction in their performance and utter obsolescence of their investments or what’s the deal?
Tell me i’m wrong and you didn’t do that to us; That you simply forgot to mention “there’s a new console command you have to enter and you just forgot to mention it” no harm done.
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Epic if true. Just pull the trigger on a pair pricy quadros + nvlink after months of pondering.
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hi ,
There is a document
Deep Dive into Multi-Process Rendering in Unreal Engine 5 | iRender (irendering.net)
with section
The NVIDIA Control Panel settings are specific to converting a Multi-GPU config to Multi-Process.
Section 3: Converting an mGPU Config
This is for without Viewport
- Use the naming conventions of the nodes we already have, name this Node_1_OS to indicate that it is offscreen.
- Disable Adding a Viewport.
- Enable Headless Rendering.
- Keep the IP Address the same to match the regular onscreen node address.
- Set the Graphics Adapte r to 1 , which is the secondary GPU.
- Click Add .
Looks like you would need for a Viewport, might work
- Use the naming conventions of the nodes we already have, name this Node_1_OS to indicate that it is offscreen.
- Enable Adding a Viewport.
- Disable Headless Rendering.
- Keep the IP Address the same to match the regular onscreen node address.
- Set the Graphics Adapter to 1 , which is the secondary GPU.
- Click Add .
You need to get the viewport going and the “r.ndisplay” is not the answer as replacment for r.AllowMultiGPUinEditor.
Briefly saw this appear to work but the display was massive. Working in front of an audience and still could not see if this is any faster and its on U.K. configure not USA configured
Who knows hope this helps 5.4 source code cannot be used as this same code is used in nDisplay now
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Sounds like the use of multi-GPU idea has evolved as opposed to abandoned. From the link provided by Jimbohalo10 the multi process rendering entails
Technical requirements:
-
-
- A minimum of two GPUs
- SLI must be disabled (If using Nvidia Mosaic, it should not be Premium Mosaic since this enables SLI)
- Disable Intel Hyper-Threading or AMD Simultaneous Multi-Threading for best performance (Note that doing this may impact other software. You can get longer shader compile times)
- Nvidia driver version 531.41 (minimum) or above tested with virtual production tools in Unreal Engine 5.3
-
i dont understand… i used to use my dual 3090s to speed up gpu related development tasks… is there an easy way to enable that now? I noticed r.AllowMultiGPUInEditor=1 isnt working.
Pretty ■■■■ stupid if its just gone…
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“Not removed, evolved” I’ll have to remember that one if i ever run for public office, because it’s pure unadulterated horse crap.
Still zero response from Epic on this and nothing but conjecture from the community, meaning indeed they assassinated it in the shadows; A feature they went out of their way to advertise just one year ago. I wonder how many people out there made the same mistake i did and “bought in” to building a rendering machine @ 3X the cost of a normal PC specifically to take advantage of this and after “upgrading” to 5.4 are wondering why their rendering is now 50% slower; Not knowing it’s because their 2nd GPU is now a worthless brick.
I’ll continue to use Unreal Engine, but as far as advocating to my followers, viewers, and colleagues in tech? Forget it; We are not friends.
at this point im kinda glad i moved away from lightmaps al together… i bought dual gpus to speed up gpu lightmass… and now i dont even get that with lightmass… terrible.
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I wanted to leave this message here before i got lazy incase anyone else finds themselves in a similar situation and came looking for hope.
So. I found out, through testing, something odd that unfortunately won’t work for me since i’m doing a production and the maximum quality of output is essential. But, maybe it’ll work for you.
So it turns out, for whatever reason, that if i switch to Vulkan and downgrade from SM6 to SM5 indeed both GPUs kick in just as they used to. In-editor FPS skyrockets. But, this means a significant downgrade in lighting and shading quality. Maybe you won’t notice, or maybe it doesn’t matter to your project, but for me it’s still a no-go. No idea why this even happens but given Epic has never once commented on this situation or explained their behavior I’m not devoting any more energy to this anytime soon.
Good luck.
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Appreciate your follow up. Been looking for a solution to speed up my cinematic renders that doesn’t involve me building multiple 4090 rigs and having each one render alternating frames but it seems like that will be my only option, even though I would much rather just put another 4090 in my current rig. Thank you!