View port (Shift+Z) use CPU instead GPU?

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1

Hello,

My Cycles Rendering (F12) using CUDA (GTX1060 6Gb) and it works fine and fast - no problem!

But when I use View port (Shift+Z) - it use CPU (i7-7700K) only on 100 % ???

GPU load only at 5-12 % at the end of process

Why it happen?

My system:
Windows 10 x64

Blender 2.79 ( 2.79.6 and 2.80 the same)
All settings in Blender set to - GPU
Driver GPU is up to date.

2

In 2.79a it seems to only use the CPU when you change the shading mode to rendered with SHIFT-Z. However in 2.80, when you have GPU Compute selected for Cycles and switch to the Rendered workspace view, it’s definitely rendering on the GPU for me.

3

Before post that topic here I was trying to find out answer on my question in Internet.

I had found existing question similar to mine - but all of them without answer.

But in some comments related to - View port render (Shift+Z)

People saying the same :

As it explained at beginning code of Blender do not suppose use GPU for View port render (Shift+Z).

But I can not find aprovment of that in manual to Blender (technical documentation)

VPperform

Maybe it is so ! Because in Performance settings (green line marked) there are options only about - CPU

Any idea about this?

May be it depend what is rendered? Some easy scene use GPU, but when it need to calculate very “hard” shaders, physics, particles so on…it allow to use only CPU???

P.S. After render in View port render (Shift+Z), when I trying to do something with my scene/objects/lights Blender is crushed. Helps only when disable that marks (red marked :slight_smile: ) …maybe it will help to somewone

4

I just tried it again, and it seems to be working correctly even in old 2.79a. You need to:

  1. Have Cycles selected as the renderer.
  2. Have the GPU selected in System->CUDA Devices
  3. Have Cycles set to GPU Compute in the Render Properties
  4. Switch the display into Rendered mode.

For me, in 2.79a, 2.79.6 (current), and 2.80 (current) it always uses the GPU for the viewport preview render when set up as above. I’m testing it with the Classroom scene.

5

Thank you @Zoot for your reply!

Just in case I had checked it all again

And my preferences is Ok ! As should be.

But It is NO changes for me, CPU - 100% after SHIFT+Z

… BUT :wink: :grin:

I have try - Classroom scene too.

And it is working as it should be :+1: ! I have GPU rendered! CPU use shortly and no more then on 23%!!!

So… That problem just in My file. I think My file use CPU just because it is “heavy” to calculate and system require CPU usage (maybe it because of out of memory !? :roll_eyes: Hard/heavy shaders, a lot of lights or too big mesh… )

@Zoot thank you a lot!

I think My problem is dissolved :smile: