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My NVIDIA GeForce GTX 780 doesn't work with Iray

LindaBLindaB Posts: 169
in Technical Help (nuts n bolts)

I've started trying to use Iray and I'm already stuck. DAZ Studio doesn't seem to be using my graphics card (INVIDIA GeForce GTX 780) and is relying solely on my CPU. Under the advanced tab in the render settings, I checked the box for the graphics card and left the box for the CPU unchecked and then loaded Genesis and did a spot render. It started to render, but the spot showed nothing, as if there was nothing at all in the scene. Then I checked the box for the CPU and it rendered. It also renders if just the CPU is checked and the graphics card is left unchecked. The rendering is super slow and my graphics card seems like it isn't being utilized at all. Does anyone have any suggestions as to what I can do at this point? Iray is so slow it's almost unusable. Thanks.

Comments

  • ToborTobor Posts: 2,300

    Restart D|S, do a regular render to a new window, and go to Help->Troubleshooting->View Log File and go to the bottom for your latest render. There's usually an indication why the GPU wasn't used. Common reasons:

    1. Your driver isn't updated to support the proper compute level needed by Iray.

    2. Your card isn't being seen by Iray, even though it's selected in the Advanced tab. Again, this can be from an old driver. 

    3. Your VRAM couldn't hold your scene. Try a very simple scene with a single primitive to see if that works.

  • LindaBLindaB Posts: 169

    I followed your instructions, and found out that the driver for my graphics card did need to be updated. The update solved the problem! Thanks for taking the time to help me out.

  • ToborTobor Posts: 2,300

    Great! On your 780, it has a lot of CUDA cores, but is a little VRAM-starved. The standard card has 3GB, and if there isn't another graphics card in your machine for the monitor display, a portion of memory will have to be allocated for that task, giving you even less to work with. Bear in mind that ALL of the scene must be able to load into the VRAM of your 780, or Iray will default to CPU-only. Keep an eye on the troubleshooting log, and see about using a utility like GPU-Z where you can do realtime monitoring of the card internals (switch to the Sensor tab, and watch the GPU load and VRAM usage during a render). Use such utilities kudiciously if your monitor is connected to the same card as the one you're rendering with; this avoids timeouts which will crash D|S.

    The 3GB limit may or may not be a big deal for you, depending on what you render. I typically only render a couple items at a time, and seldom big scenes, so the VRAM  shortage isn't a big deal for me. I don't have a 780 myself (wish I did), but even one of my 2GB cards will usually take the full scene of my typical renders.

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