Open CL very, very slow or even doest't start!

My GPU is Radeon RX 580 8gb RAM driver ver 19.8.1
after changing rendering engine from CPU to Open CL in a settings -> cycles, a whole model renders very slow in raytrace mode. Even 10 times slower than in CPU mode.
After installing the newest driver for radeon ver. 19.9.2 the Raytrace process doesn’t even start.


Our current OpenCL support in Raytraced is indeed sub-optimal. I’m working on rebasing our Cycles version on top of latest upstream Cycles (Blender Cycles). There have been quite a few optimisation that hopefully make things better for us too.

If you just installed latest driver Raytraced needs to recompile the kernels first. It can take quite a while.

Dear Nathan,
thank You for Your fast reply. So I guess the Open CL engine will be optimal in Rhino 7, right? Could You tell which version of driver is better now: 19.8.1 or update to 19.9.2 and wait as the recompile finish?

Thank You

I don’t know what the best driver is at the moment, I am still on 18.9.3. But waiting for compile to finish should be fine (assuming the driver doesn’t fail to compile the kernels).

I hope in V7 it’ll be improved, but I’ll know more once I’ve completed the rebase. It’ll take a few weeks to get through the process.