Dual RTX 3090 GPU

[Jeroen]

I build a dual RTX 3090 GPU system with a NVlink bridge between both GPU's. Both GPU's are working well....but when I start rendering it only uses one GPU. Do I somewhere have to activate the 2nd GPU for Archicad?

[Laszlo Nagy]

You say you are rendering.
If you are rendering with CineRender, that will use the CPU, not the GPU.
Or are you rendering with Twinmotion or some other GPU-based rendering solution?

[Jeroen]

I use the standard Archicad render option. So that's cinerender I guess? (Sorry, I'm a IT hardware guy, not an Archicad user myself)

If I understand right: two RTX cards doesn't help Archicad in speed? I thought I read it in the advice specs...but guess I was wrong(?)

[Laszlo Nagy]

All Rendering Engines you see in the PhotoRendering Settings Dialog (Basic Renderer, CineWare by Maxon, Sketch) are CPU-based rendering engines.
The OpenGL Engine is used in the 3D Viewpoint, when you are viewing, editing, navigating your model there. OpenGL is using the GPU, and the following article covers the suggested graphics card for Archicad 24:

https://helpcenter.graphisoft.com/knowledgebase/127710/

I would be interested to know where you read about multi-GPU and Archicad (Nvidia SLI or AMD CrossFire). I do not see any such information in the above article. As far as I know, programs have to be additionally coded to take advantage of multi-GPU hardware, and I am not aware of any such development in Archicad. But I may be wrong, so if you could provide the link to the source of that info, I would like to read it.

[Jeroen]

I can't find the article I found about dual GPU in Archicad. I'm afraid it wasn't an article of Graphisoft itself and the information maybe wasn't right.

For now I'm switching back to one GPU. If I find the article again I'll inform you. For now thanks for the help!

[sboydturner]

Jeroen,
If you use the Octane Render plugin for rendering it will use as many graphics cards as you can put in the system (not in SLI) but this is not the included rendering engine in Archicad.

Regards
Scott