The key thing I'm seeing in the log you shared (thank you) is:

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iClone 7... Character Creator... Substance Designer/Painter... Blender... Audacity...
Desktop (homebuilt) - Windows 10, Ryzen 9 3900x CPU, GTX 1080 GPU (8GB), 32GB RAM, Asus X570 Pro motherboard, 2TB SSD, terabytes of disk space, dual  monitors.
Laptop - Windows 10, MSI GS63VR STEALTH-252, 16GB RAM, GTX 1060 (6GB), 256GB SSD and 1TB HDD

I am having the same problem. 
I think these are the pertinent lines from the iray render log.

1.6 IRAY rend error: CUDA device 0 (GeForce GTX 1080 Ti): Kernel [6] (EnvironmentMatte ) failed after 0.008s
1.6 IRAY rend error: CUDA device 0 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while launching CUDA renderer in core_renderer_wf.cpp:771)
1.6 IRAY rend error: CUDA device 0 (GeForce GTX 1080 Ti): Failed to launch renderer
1.2 IRAY rend error: CUDA device 0 (GeForce GTX 1080 Ti): Device failed while rendering
1.3 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while allocating memory)
1.3 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): Failed to allocate 4 B
1.3 IRAY rend info : CUDA device 1 (GeForce GTX 1080 Ti): Used for display, optimizing for interactive usage (performance could be sacrificed)
1.6 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while allocating memory)
1.6 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): Failed to allocate 120 B
1.6 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while resolving mapped memory)
1.6 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while launching CUDA ior stack renderer in core_cuda_host.cpp:385)
1.3 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): Failed to update ior stack
1.3 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): Device failed while rendering
1.3 IRAY rend warn : All available GPUs failed.
1.3 IRAY rend warn : No devices activated. Enabling CPU fallback.
1.3 IRAY rend warn : Re-rendering iteration because of device failure
1.2 IRAY rend error: All workers failed: aborting render
1.3 IRAY rend error: CUDA device 1 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while de-allocating memory)
1.2 IRAY rend error: CUDA device 0 (GeForce GTX 1080 Ti): an illegal instruction was encountered (while de-allocating memory)

BTW I used IRAY in DAZ studio and everything worked fine there. Also, I have been using IRAY in iclone since it came out without any problems until yesterday. I have all the latest drivers. I have already uninstalled and reinstalled the plugin. 

Any help would be much appreciated.
Thanks,
Craig

Try going into your "Iray Render Settings" and click on "Hardware Settings". Now check to see which graphics cards are listed and ensure the right one is checked.

Then for the purposes of testing, take out the check from CPU which will force the Iray rendering to use only the chosen graphics card. Does this improve or worsen the time it takes to preview render?




                                                                

Peter
Forum Administrator

www.reallusion.com

I've got the GTX 1080 t1 using the Nvidia 411.70 driver. It worked fast. I upgraded the driver to the latest 418.11 and I immediately got the GPU "out of memory" as soon as the render started. I rolled back the driver to 411.70 and everything is fast again. Don't know if this could be your problem. 

https://www.artstation.com/pascalcomics
https://www.renderosity.com/users/Pascal_Comics/gallery
https://www.deviantart.com/pascalcomics/gallery

Thanks for the tip. I rolled back to the older driver and now IRAY is working again with small projects. It seems to be having problems with complex scenes. 
FYI - The new driver worked in Daz Studio as well as the old driver.

Craig

Glad it helped. As for the complicated scenes, I loaded a project with a bunch of Speed Tree grasses and trees and sunflowers and iRay choked and disappeared off the screen but it left iClone standing. I guess that's a good thing.




https://www.artstation.com/pascalcomics
https://www.renderosity.com/users/Pascal_Comics/gallery
https://www.deviantart.com/pascalcomics/gallery

If you have complex scenes, it does help save resources if you hide anything in the Scene Manager that's not in view, reflects, or casts a shadow.

So if you have an animation with different camera angles, it would be better to render one camera angle at the time, allowing you to hide items that do not contribute to the scene.

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I only have 1 Graphics card. and that is the 1070
I did try uncheck CPU and then it seems to me, that there is no difference at all.

I might have to do that,  even though I am not getting a memory error,  but I do have the latest driver installed

Installed the 411.70 driver, and no difference.
I did notice that even if your done with a preview and close it,  it doesn't free up the GPU memory.
I start out with 4.5 Gb  and when doing is 2-3 times, it's at 7.5 Gb.
Even closing the preview doesn't release the memory. or whatever.
Played with all the settings, and the only one that makes somewhat a difference is when I change the preview screen size to 320x240 and zoom in.
The default 1000 x something,  is making is slow..   even 640x480 preview is slow.

How does the smartcache work?  do you need to enable something, since I don't see a difference.
Then I still have the fact, that once it's done, and I zoom in or move the camera, it's still take a long time before I can move again.. there is a huge deley between the movement
and the preview starts doing something.