multiple 3090s for massive Blender render (lots of RAM)

Numbafieve · July 31, 2023

I am currently working on a huge render in blender. I have found i need about 120GB of system memory and about 50GB of VRAM to do this with no page files or memory swap into system (which i dont have enough of anyway). Right now i have a 5950x (OC to high hell, 4.8GHz all core)

64GB of CL14 3777 DDR4

3090 + 1050ti to run extra monitors

all water cooled and with a good PSU for now

The problem is that I am obviously running out of both types of RAM, Blender even tells me this. I have a 128GB kit of DDR4 showing up later today and am currently looking at buying a slightly broken matching 3090 that I can fix. I have been looking but cant find any definitive answer as to if having 2x3090s will stack the VRAM or not. I know in the old school SLI days it did not but I was under the impression that most render engines like Blender that was not the case and the GPU memory could actually stack. If so ill probably get 2 more 3090s and a 4090 for this system and then build a render farm for future use with the 4x3090s and 512GB of RAM.

If anybody has any experience or can find some bit of info about blender I wasnt able to that would be fantastic. I cant even attempt this render until I get some kind of fix for this issue, and obviously I cant get paid for this project until I do actually get it rendered.

GuiltySpark_ · July 31, 2023

https://docs.blender.org/manual/en/latest/render/cycles/gpu_rendering.html

3090's do support NVLink so that might be a viable option.

Numbafieve · July 31, 2023

2 minutes ago, GuiltySpark_ said:

https://docs.blender.org/manual/en/latest/render/cycles/gpu_rendering.html

3090's do support NVLink so that might be a viable option.

Awesome straight from ze manual. I looked through it but couldnt find anything specific to my case. I did see something about possibly needing NV link to increase memory from somewhere else. Guess thats the way I will have to go. Probably will try it without first but I have to do what I have to do I guess.