CPU Vs. GPU Rendering - Should I Uncheck CPU?

tristanthorne1997

In the The Render Settings Window, there's a checkbox for CPU and one for my GeForce 970 GPU.  Both are checked. Is there any reason I would want to uncheck the CPU one? I just did a fresh install of Windows 10 and Daz Studio to attempt to correct multiple crashes caused, I believe, y conflicts between my GPU and Win10. 

SixDs

I'm not sure that there is any good reason why you would need to uncheck CPU rendering. If GPU is checked and you have an appropriate Nvidia-based card, then the GPU will automatically be used for rendering, regardless of whether the CPU is checked or not. The exception to this would be if the GPU has insufficient frame buffer (memory) to hold the scene you are rendering, in which case Iray will default to the CPU. Having the CPU unchecked in the latter scenario would simply mean the scene would not render at all, presumably.

agent unawares

SixDs said:

Having the CPU unchecked in the latter scenario would simply mean the scene would not render at all, presumably.

Unfortunately it still drops to CPU in this case.

Personally, I uncheck CPU. At the power of a GTX 970 your CPU will be making little difference to the render time, and will slow you down from doing anything else meanwhile if it is used for rendering. Better to go GPU only.

BeeMKay

Actually, having both checked will make the render slightly slower, if the Iray Benchmark test is any indicator.

tristanthorne1997

Thanks everyone. I am going to try the Uncheck CPU method and see if anything bad happens :)

It woud be nice if it sped up the renders!

BeeMKay

You can always use the Iray Benchmark scene for testing and comparision. https://www.daz3d.com/forums/discussion/53771/iray-starter-scene-post-your-benchmarks