SOLVED: GPU to CPU rendering issue for GTX1080

btymoffers

Hey Guys, After a month of being plagued by my gpu's being switched to CPU mid render. I finally figured out what the issue was.(just read the conclusion if you want the answer quick xD below is just a bit of the story)

 

So I have two 1080sc 8.2gb video cards.

Commonly I'd make a scene to render, and it would be like anywhere from 3-5gbs on the canvas. Which was fine. It worked great, rendered quickly, so on- so forth.

Recently I've been making much larger scenes, that were animated. But started running into an issue.

It would render the first frame flawlessly. However, the moment it switched to the second frame, thats when s*** hit the fan (excuse me). Instead of continuing the render on my GPU's that weren't fully being used, it would switch to the CPU to continue the rest of the frames... This issue has litterally drove me up the wall several times, and almost caused me to scrap a project because of it. I spent hours trying to find a fix. At one point I had determined that the issue was Geometry related, and that is was stockpiling it, but that ended up being just a specific tree asset I had that was causing that issue. I Messaged support, they weren't sure what was going on. Many places said stuff like, lowering texture compression value, or lowering the resolution, enabling Optix Prime Acceleration (which I already had on), lowering Bump Map, reducing gloss and or specular maps, changing gloss method, adding more light... You get the picture...

Anyway, it turns out... for me and my GTX 1080's, the issue was OptiX Prime Acceleration.

Honestly the moment I disabled that (supposed Highly reccommended feature, for those with more recent nvidia cards) My render times cut in half, it started using all of my available VRAM, and stopped erroring out in some scenes.

 

Conclusion: If you have GTX1080/'s and you want faster render times, or you want daz3d to actually use all of your VRAM without crashing, or switching to CPU,            uncheck OptiX Prime Acceleration. Solved all my issues.

I'm uncertain of the case with other video cards in 10xx Series. But it appears to definately be the case with the 1080.

 

Hope this helps people with similar issues. Also, please comment if this ended up fixing the issue for those of you with different video cards.

 

(PS: Sorry for writting that speel before the fix, I had to vent a bit cuz this was an infuriating issue for me, hehe.)

fastbike1

Optix Prime has been hit or miss with People since Iray release. When it works it generally seems to make little or no difference in render time. When unchecked render times don't seem to be affected other than not being dropped to CPU.

ruscular_2abdb5da28

It hasn't for awhile and suddenly I was having issues, and thought it was heat related. This is good to know!