Very surprised UE 5 isn’t using more than my primary GPU for VRAM and overall processing etc. I’m coming from years of working in Davinci Resolve; each identical gpu added to the machine (without SLI or NVLink or anything like that), the system performance instantly increases by around 40%. DR will make use of the 2nd GPU VRAM and overall processing power.
Will UE 5 have the same capabilities?
I see my CPU usage absolutely max out in UE 5 - same with system RAM and VRAM on GPU 1.
But GPU 2 is untouched… GPU 1 is doing essentially ZERO processing, maxxing out VRAM, and GPU 2 with zero VRAM usage and zero processing…
Is there a plugin or something I can install to actually utilize all this hardware sitting here?
I get that PUGET SYSTEMS demonstrates that money is currently better spent on a 64 core CPU. But the performance gains I experience in Davinci Resolve with multiple GPUs is what I was expecting in Unreal Engine, especially this latest release.
I want Multi-GPU support for UE5 as well. I want to be able to just add another RTX A6000 to my workstation when I want to upgrade instead of basically having to buy a whole new computer to upgrade.
Can anyone from Epic shed some light on multi-GPU plans for UE5?
I’m in the same boat, I have been trying to get Multi GPU running in Unreal since UE4 and it still not looking great in UE5. From my research there is a couple of commands targeting DirectX 12 mgpu but the engine just crashes when used in conjunct with ray-tracing or Lumen. The commands I found must be run on the .uproject which are:
“-game -d3d12 -MaxGPUCount=2 (or number of GPUs in your system up to 4) -AFR”
and if you want to test a multi GPU setup with a single GPU system you can add -VMGPU. I also found these console commands that you can add to your ini config file:
r.AllowMultiGPUInEditor 1
r.EnableMultiGPUForkAndJoin 1
r.PathTracing.GPUCount 2
D3D12.AFRSyncTemporalResources 1
D3D12.AFRUseFramePacing 1
r.GPUParticle.AFRReinject 1
An example if you want to try it on your system is to run this in CMD (Command Prompt):
Also go to your project config folder “C:\Users\Public\Documents\Unreal Projects\UE5Test\Config” then edit DefaultEngine.ini if there is no [/Script/Engine.RendererSettings] section add it and the add:
Added support for multi-GPU rendering (mGPU). SLI is required. To enable it, pass -MaxGPUCount=2 on the Unreal Editor command line and set r.PathTracing.MultiGPU=1, which can be toggled at runtime. (r.AllowMultiGPUInEditor=1 is no longer required in .ini files to enable mGPU in the editor.)
Not every project is targeted for real time. It will be a while before path tracing will be possible in real time. For those of us who do filmmaking or cinematics, relying on a single GPU is quite limiting. Non-real time 3D apps have all pretty much moved to XPU. UE needs this if it wants to play in the path traced game, especially when NVlink was killed off by Nvidia.
I have a rendering system w/ 2x A6000 (NVLink enabled), would love an update on this for 5.2. I haven’t been able to get multi-gpu working yet (5.1.1).
I found out from testing out the r.GraphicsAdapter console command today (set in BaseEngine.ini) that you also can’t switch processing to GPU1 (from GPU0) with NVLink enabled. I mean it technically works, however the editor screams at you about your hardware not supporting DX12/SM6. It would at least be nice to offload UE processing to GPU1 (since everything else running on the system is using GPU0)
So alas, my 2nd GPU continues to sit there, VRAM and Core unused for UE work
Same here. We have 2 x A6000 (nVlink enabled) But, we are unable to use the multi-gpu !
Can you please help us, if you have figured out already. Thanks.
