Hardwares and related performances

linoge8888

Well, I read everything and its opposite about how the hardware works within DS. I'm sure of one thing : the more powerful GPU, the faster rendering. Please could you tell me how the following is affecting DS performances :

- VRAM : rendering bigger .duf file ?

- RAM : smoother navigation in viewport ?

- CPU : ?

- About fluidos, which hardware must be focused on for a faster simulation ? 

jparks123

If your scene cannot fit into VRAM, the GPU will not be used. The CPU will do it instead, and rendering will take probably about 10-20x longer.

CPU will affect viewport response time. Certain operations like loading (and maybe LIE texture generation) appear heavily dependent on single core CPU performance rather than the number of cores. Loading especially; I can see the CPU usage maxing out a single core while the others are idle.

Low system RAM will give miserable performance all round. Make sure you have at least as much as VRAM, ideally more (probably VRAM x 1.5).

You do also need a fast SSD unless you want the user experience to be miserable for loading.

I have no experience with FluidOS.

 

linoge8888

Thank you, I'll ask in the Fluidos official thread. 

PerttiA

jparks123 said:

If your scene cannot fit into VRAM, the GPU will not be used. The CPU will do it instead, and rendering will take probably about 10-20x longer.

CPU will affect viewport response time. Certain operations like loading (and maybe LIE texture generation) appear heavily dependent on single core CPU performance rather than the number of cores. Loading especially; I can see the CPU usage maxing out a single core while the others are idle.

Low system RAM will give miserable performance all round. Make sure you have at least as much as VRAM, ideally more (probably VRAM x 1.5).

You do also need a fast SSD unless you want the user experience to be miserable for loading.

I have no experience with FluidOS.

Three times more RAM than VRAM 

linoge8888

PerttiA said:

Three times more RAM than VRAM 

You mean the minimum ? I read someone had 128 Go of RAM and was enjoying it a lot.  

PerttiA

linoge8888 said:

PerttiA said:

Three times more RAM than VRAM 

You mean the minimum ? I read someone had 128 Go of RAM and was enjoying it a lot.  

Yes, minimum. In any case 32GB's or more. 

outrider42

VRAM is max your capacity, if you exceed your VRAM, the GPU will simply not run. It will be a paperweight. So no matter how fast and awesome a GPU is, the VRAM is its ultimate limit, and if its VRAM is low, the speed is kind of pointless if you cannot make use of it. Usually the faster GPUs have more VRAM, especially at the top like the 4090 and 3090.

RAM is also important, but unlike VRAM, you can add more RAM to your system at any time. Iray compresses data that it sends to GPU, this is why Daz people say you need more RAM than VRAM. Exactly how much can vary wildly though. It just depends on what you want to do, and what Iray compression settings you use. By default it actually compresses quite a lot, and that is where you see people saying you need 3 times more RAM than VRAM.

But how much memory you need depends all on you. What are you trying to do? Are your scenes fairly simple, like portraits of one or two people? Then you may not need a ton of memory.

CPU is not as important for Daz Studio. Yes, it can impact how well the viewport runs, but unfortunately Daz Studio mostly uses just one core on any given CPU. Thus a big 16 core CPU is not going to help you all that much. Most modern CPUs are pretty decent compared to those of the past. Like a mid range CPU is not a dramatic drop off from the high end ones. Plus you are going to be using your GPU to render, not your CPU. So if budget is an issue, the advice for DS is to always focus on the GPU first as it is far more important.

The GPU can also handle the viewport. So again, a good GPU is helpful. The CPU does do some things, like handling mesh data, so you don't want to skimp too much on CPU. But you don't need the best CPU, either. Just a capable one. Building a large scene can slow down the viewport...but this is more of a software bottleneck than a hardware one. Supposedly a new Daz Studio 5 is in the works and maybe they will fix this, but DS5 has been "coming soon" for over 3 years now. What does "soon" mean??? Nobody knows. But we don't even know if DS5 will use more cores, I am only assuming that a modern piece of software will actually be modern.

You can also use multiple GPUs with Iray, too. Each GPU needs to be able to fit the scene in its VRAM. Like if you have 12gb and 8gb GPUs, and you build a scene that uses 10gb, the 8gb GPU will be idle and not render the scene. If you build a scene that is under 8gb, then both GPUs will render together, combining their compute power to render much faster. If you build a scene that is over 12gb, then no GPUs will render!