This appeared when I mirrored an object with the subdivision surface modifier:
When I tried to auto-mirror the object, this appeared, and the mirror modifier didn’t show up. I already found a solution by putting the modifier directly (through the object properties panel). I want to know why this is appearing and how to prevent it from occurring again. I am using the 4.2 version by the way.
I looked into this a little - this is just a low-grade informational message (as in “not even a warning”). It looks like the reason is because using both units at once instead of just the GPU can actually increase rendering times, but there doesn’t appear to be an option to disable CPU rendering in the Subdivision Surface Modifier itself. The only option is to disable GPU rendering, which you basically never want to do, for obvious reasons.
You can try the things listed here, but I’m not sure if they’ll stop this message or not:
https://www.reddit.com/r/blender/comments/16yl4q8/can_anyone_tell_me_why_this_using_both_cpu_and/
It likewise confuses me and no one seems to know if it is good or bad or makes any difference or how to make it do anything differently.
Some processes can only be done by the CPU and then passed to the GPU. I tend to presume that is what is happening.