GPU Rendering: VRAM needs ?

[mafrieger]

moved from: https://forum.keyshot.com/index.php?topic=26165.0

To choose the best GPU (in normal live and in case if money wouldn't matter):

Some questions regarding usage of GPU's VRAM:

1) what's biggest VRAM amount needed for a scene you have seen so far?

2) What are the things that drive VRAM amount up most?

3) Could you share a demo scene with very big VRAM needed?
With this one (jet3d and others) could see if a / a couple of Quadros with lots of VRAM is/are worth it / needed (in real live)...

[smalldogstudio]

Hi, great topic btw

I had a recent scene which was 28M Polys, lots of textures with 3-4 layer labels, rendering at 4k to 500 samples - it went beyond my 6GB GPU size. It became hard to work with, so i ended up re-doing all my textures for the labels (there were lots of them) at 200dpi, they were originally 600dpi as they were used fro individual pack shot renders. I simplified the objects as well, removing an outer 'gloss' layer and reducing the number of layers in the label. I do a mixture of HDRI and HDRI+Physical and also just physical depending on what I'm trying to achieve.

From my experience, every scene starts at 2GB when using GPU, so you effectively use up 2Gb of your card memory just loading the code necessary to perform the render? (please correct me if I'm wrong).

the issue is I suppose that GPU cards with lots of memory quickly get very expensive - e.g. 11GB RTX2080 = £1k+ in UK.

I could share a stripped back scene (without the real textures and objects replaced due to confidentiality) - but I'd need a few days to sort it out

bw

David

[mafrieger]

maybe it would be possible to add something like a forecast/sum up of needed VRAM or and even RAM ?
with this one could easily
- tune it for fit
- understand during work what kind of hardware upgrade would be nessesary?

=> would help a lot to understand ist there just 1GB VRAM missing or is it 12GB to make this scene work smooth..

[Justin A]

When running GPU mode if the display hud is up on the real time render view you will see even in an empty scene there is Vram being used.
This is due to other processes running eg. Windows, background apps etc. typically it will be around 30% of the Vram on your card.

I have an RTX Quadro 4000 and I have had scenes with around 15-20 million triangles be to heavy for this card.
We have however introduced the use of NVlink which will allow you to double the amount of Vram you can use on your PC.


Thanks,
Justin