Can't set my rendering device to OpenCL GPU

[pes-]

Hello,
when rendering only CPU gets used. In render settings I've selected OpenCL as the rendering device, when I click Update OCL device list "Ellesmere" tick box shows up. It still doesn't render with GPU.

I have
Radeon RX 580 Series, all drivers up to date
Intel i5-7500
win 10
LuxCore 2.3

In LuxMark when rendering, there is OpenCL_GPU and platform: AMD, Inc. under Ellesmere, under GPUs and Accelerators. But it still uses the CPU.
Could you please help me?
I'm sorry if it's something trivial, I've searched everywhere but couldn't find anything.

[Dade]

Only the CPU or both the CPU and GPU ? I ask because, by default, LuxCoreRender uses both if you enable GPU rendering.

[pes-]

Even when I disable the CPU tick box it uses just the CPU

[Dade]

Even when I disable the CPU tick box it uses just the CPU

You may have an OpenCL CPU devices and it should be not used but still LuxCore can use native CPU threads too for the rendering and they are enabled by default. Under the Blender performance panel, you should have a GPU section and a CPU section. If you unchecked the CPU device section, it should be not used.

[pes-]

When I uncheck it and render, Blender still doesn't use any GPU power, only the CPU gets 79% while GPU 0% in the task manager.

[CodeHD]

I don't know how the task manager defines GPU usage but this seems to be normal behavior in windows. I also see 0% GPU usage there, and GPU rendering definitely works.

Also you will always get CPU usage because there is auxilliary stuff to do, for example data transfer to the GPU to manage.

Try to render a simple scene (e.g. the default cube) and observe the samples per second for the three possible settings, i.e. CPU only, GPU only, CPU+GPU, you should see a clear diference.

What you should observe in the task manager is a change in the GPU memory. I see it even for the default cube.

EDIT: I just noticed that the task manager offers you a dropdown menu to show different GPU performance aspects. The default is "3D", which shows nothing. In my case, with an NVidia-card, I have to use "CUDA" to see the the GPU being used by LuxCore.

[pes-]

Thank you!
I didn't realise it worked like that,
thanks very much again!