I've been able to get out of core rendering since that last 2.79b experimental build

Hi I was just saying to someone on facebook that blender has out of core rendering when gpu rendering (so it can render scenes that use more memory than the GPU has), but the guy says he’s getting the cuda error when he runs out of vram. I’ve just checked the manual and it says out of core isn’t possible…

I’ve been able to render any size scene on just my 1070 since the latest 2.79b experimental branch (scenes that use 20gb and upwards which used to give me the cuda error prior to installing the latest 2.79b experimental). How is it possible I can get out of core if the manual says it’s not possible?

Here’s a scene using 9gb ram rendering happily on the gpu: