Memory and GPU memory usage question

[Yoshiii335]

Hello,

I read somewhere that some 3D professionals and tech professionals said that in order to get full usage out of a gpu's memory for 3D work, productivity work you have to have lots of ram. Example they gave was using a gpu with 12gb of vram, you need at least 24 gb of ram, etc. Is this true?

 

[ir_cow]

Kinda, It just depends on the dataset. If the project being rendered exceeds the vram, it will go a lot slower or not work. Its been a while since I looked into this, but at one point (2-3 years ago) Adobe Premiere and Blender (two examples) would dump all the project assets into the vram. If it fills up, either the software crashes / fails to render or is very slow. Might even be worse vs just the CPU.

 

[_Flare]

The question was if a too small RAM can/will hinder the GPUs effective usable VRAM in professional usecases, right?
If so, my first two toughts were about:
- the swap-file wich typically sits on a drive and should not play any obvious role for answering your question.
- the second tab of the dxdiag program in windows
There are 3 numbers in this mentioned 2nd dxdiag tab and none of them seems to be obviously related to the systems RAM, but wait a minute
- approx tot. memory is about the double size of my VRAM and which physical memory is used by that "shared memory" (my system has 8GB VRAM and 16GB RAM)

When you have an integrated or dedicated GPU, your operating system will take up as much as half of your RAM and use it as shared GPU memory.
So it´s not the size of the dedicated VRAM wich sets the size of the virtual shared VRAM in your systems RAM, but the OS, Windows will reserve half of your RAM regardless.

That, to the uninitiated, might seem strange, but there’s actually a very logical explanation behind it all.
https://www.cgdirector.com/what-is-shared-gpu-memory/

 

[ir_cow]

The question was if a too small RAM can/will hinder the GPUs effective usable VRAM in professional usecases, right

Yes I see now. Misunderstood.

Yeah, besides onboard graphics, you don't need double the system ram of the GPU vram. only reason to have more memory is for the program open.