CPU usage over GPU

I Have noticed recently that when i put my system for Rendering with one Gen 9 the render uses 95 to 99% GPU and Cpu goes 15% to 23%.

And when i add another Genesis Character that is with two Gen 9 , the render uses 99% CPU and GPU is not used during this time which results in slow rendering.

can anyone help me with this or is this normal?

 

My System specs are as follow:-

Acer Nitro 5 Laptop

I7 12650H

Nvidia 3070ti 

Ram 32GB (16+16)

storage is on SSD of 1tb 

Comments

  • lorraineopualorraineopua Posts: 642

    Normal behaviour. The scene must fit into the vram of GPU and when it doesn't, it drops to using the CPU.

  • is there any other way to make it use gpu to render faster and save time??

  • Nope, although it sounds like the scenery might be your issue, and not the models. Although if your 3070 is only 8gb, that's a little small for current usage,. You could try removing any unneeded scenery and see if that helps. Hide anything not visible to the camera.

  • felisfelis Posts: 4,338

    Textures can be eating a good amount of VRAM, so you can also benefit from something like this https://www.daz3d.com/scene-optimizer

    You can often go to 2k textures, without being noticable, or even 1k if a bit further away.

  • let me try this out and see.

    BTW Thnx a lot for helping out

  • MouserMouser Posts: 675

    I almost got 3070 but opted for the slower 3060 but with 12g of vram and at times 12g is only just enough.

  • jbowlerjbowler Posts: 794

    lorraineopua said:

    Normal behaviour. The scene must fit into the vram of GPU and when it doesn't, it drops to using the CPU.

    In "render settings" "Advanced" tab select the "Hardware" subtab  (gee, please simplify these interfaces!) and in the "Scheduling" subpane uncheck "Allow CPU Fallback", shut down DAZ, check it is still unchecked (instances destroy the setting but if you use instances you already know all about that) and then when the GPU OOMs you get a nice black render window kind-of fast.

    Not doing this, allowing the CPU fallback, will basically make your video card an expensive waste of money simply because you will make more complex scenes (like, two dudes in the scene, not one?) and then just render them with the CPU, which you had anyway without giving NVidia your pension.  It should be the default.  DAZ: you guys know the CPU render is completely different to (US than?) the GPU render.

    UI Piccie:

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  • kprkpr Posts: 113

    JBowler is correct, those instructions will stop Daz3D using the CPU at all... but requires a restart and as put, you will then get "no render" if your scene maxes your VRAM.

    If you want to sometimes use your CPU then you can simply uncheck your cpu for a particular render (no restart required).

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  • PadonePadone Posts: 3,700

    One bad habit of iray is it will not render on the gpu anymore once it drops out of it, even if you then simplify the scene. Unfortunately you have to restart daz studio to get the gpu up and running again, that in my opinion is a massive waste of time and probably a bug.

  • Pretty much any render I do with 2 or more figures (G9 or G8) uses about 99% CPU and anywhere from 65 - 98% of the GPU (it jumps around during the render, but averages in the low 90s). It also takes its sweet time and sometimes even crashes. Would the above settings be prefereable for me at all?

  • PerttiAPerttiA Posts: 10,024

    teechurz_7c41d96282 said:

    Pretty much any render I do with 2 or more figures (G9 or G8) uses about 99% CPU and anywhere from 65 - 98% of the GPU (it jumps around during the render, but averages in the low 90s). It also takes its sweet time and sometimes even crashes. Would the above settings be prefereable for me at all?

    What are your system specs?

    Which GPU and how much VRAM it has?
    How much RAM does your computer have? 

  • I've got an AMD Ryzen 9 5900 CPU, with a GeForce RTX 3080 (with I think 10 GB of VRAM) and 32 GB of RAM.

  • kprkpr Posts: 113

    teechurz_7c41d96282 said:

    Pretty much any render I do with 2 or more figures (G9 or G8) uses about 99% CPU and anywhere from 65 - 98% of the GPU (it jumps around during the render, but averages in the low 90s). It also takes its sweet time and sometimes even crashes. Would the above settings be prefereable for me at all?

    Yes. Uncheck your CPU. Because you have both selected seems Daz will use both, and your CPU will be much slower than your GPU for rendering.

    (for how - see the image I attached a couple of posts above yours)

  • kpr said:

    teechurz_7c41d96282 said:

    Pretty much any render I do with 2 or more figures (G9 or G8) uses about 99% CPU and anywhere from 65 - 98% of the GPU (it jumps around during the render, but averages in the low 90s). It also takes its sweet time and sometimes even crashes. Would the above settings be prefereable for me at all?

    Yes. Uncheck your CPU. Because you have both selected seems Daz will use both, and your CPU will be much slower than your GPU for rendering.

    (for how - see the image I attached a couple of posts above yours)

    I did that and now it works great!  Thanks!!

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