I haven't used iClone and Iray for a couple of months, but just for a test after reading about Iray here in the forums I loaded a project.
Checked hardware settings for Iray, and I see my GTX 1080 Ti. Oh btw I deselect CPU's.
Then I click preview.
Ok fans on the computer starts to sound like a concorde take off and absolutely nothing happens.
Even the preview window that show iterations shows up like a black screen.
While "rendering" I looked at perfomance via task manager. GPU does nothing, not even the inbuilt one on the motherboard.
This also happens with a new project, just a few cubes or spheres.

Any ideas?

Edit: The CPU load doesn't go up either. I have a i7700 4.20 GHz (4.5)

1st off never deselect CPU that is the brains of your computer, you cant do anything without a brain!, you can adjust the amount of threads used but if you do not know what you are doing, do not change anything with hardware.Every CPU has a core count and a thread count. Iray is a CPU intensive program it will eat your V Ram then default back to the CPU as its coded to do.

Iray was 1st designed to be CPU thread intensive not GPU...
If you want a monster iray render machine then buy an AMD thread ripper chip with 48 to 64 threads.
Even with 5 Titan Rtx cards with 24GB vram...  Iray will still eat them up and default back to the CPU cores and threads.
A 1080ti is a good card but iray will eat it up like its nothing. You can actually over heat a card and cause
hardware damage.

Put all your hardware settings back to default and enjoy the software. ..



Freelance Artist Kevin.S



  

Email: animatemyart@gmail.com - Web Site:  www.animatemyart.com

Thank you for replying.
First version of Iray worked well. CPU and cores and GFX available.
And I renderd wit GPU only and it was fast.
But now even the CPU and GFX do not seem to bother.
What I read:
"Also, let's say that you have a very powerful graphics card, then it is entirely feasible to uncheck the CPUs option to assign the render task entirely on the graphics front"

--- link ---
http://manual.reallusion.com/Iray_Render_Plug_in/ENU/1.1/Default.htm#Iray_Plugin/1.1/07_Render_Settings/Hardware_Settings.htm%3FTocPath%3DRender%2520Settings%2520Tab%7CRender%2520Settings%2520Section%7C_____5
--- link ---

Two weeks ago I reinstalled older drivers because the newer drivers seem to be the culprit. After I reinstalled the older drivers everything worked fine. GPU's 2-1080ti's were working with and without the CPU. Then I got an update for the Reallusion Hub and iray stopped working again. This was with the same driver and everything else the same. 
I can't say if that update did anything to affect the way the graphics drivers worked. It seems unlikely.
So, installed the latest creative version of Nvidia's latest drivers. I still have the same issue, 
I also noticed that some of the people over in the DAZ world are having similar issues.  But, everything works fine for me in DAZ.
I am going to try and get to the bottom of this. If I do I will let you know.
Craig

Sorry had to leave before posting and I had more to say : ) I was in a rush.
Yes the CPU is a nice thing to have but in this case I wanted to benchmark a bit.
But strangely when looking at performance nada happens, onboard intel nada, nvidia nothing.

Btw Kevin S nice pics

Ah thanks Craig.
Yesterday my Win 10 update installed new Intel Gfx drivers. I just sat there and hoped that
it wouldn't overrule my nvidia drivers.

I'm using Iray with my GTX 1080 ti and CPU rendering turned off, without any catastrophic failures. Deselecting the CPU doesn't mean it isn't used at all, it just means it is not used for the actual rendering task, which is more efficiently performed by the GPU. 

Newer drivers could indeed be an issue. I'm using the 417.35 version, which works OK.

For serious rendering tasks, I use the stand-alone Iray renderer. Using iClone and Iray at the same time may be more than the GPU can handle. If you don't have it, I recommend GPU-Z to monitor GPU VRAM usage.

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I intuitively kept my 3 month old NVIDIA driver even with a new card, since a few weeks ago i read a post here about something broken with the latest one.
It seems a bit unbelievable to me that something like that isn't acknowledged by RL yet. Maybe i'll give it a try to confirm.

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As I mentioned above, the IRAY plugin stopped working. But, now it is working again. The only difference is that Windows did a little update. I shut down my computer after the update and rebooted. IRAY is working. 
Not sure why. BTW I am using the latest Nvidia Drivers for Creatives. https://www.nvidia.com/download/driverResults.aspx/145178/en-us
Craig

As you will find on Daz Studio forums,iRay requires frequent computer restarts to clear cache. 

Nathan