[Bf-cycles] CUDA performance tests

[Brecht Van Lommel]

Thanks for the extra information, very helpful.

On Sun, May 18, 2014 at 10:55 PM, David Black <db4tech at yahoo.co.uk> wrote:
> Conclusion with my heavy scene:
> Windows 7 x64, GTX 580m 2GB.
> With Blender 2.70a total memory used 1540, since recent Blender versions use
> more memory (1743) for the same scene there is limited space left for render
> kernel. Removing just one of my high resolution textures also works, then
> total memory used is 1688, it would seem the kernel needs at least 300MB
> spare for full performance? Less than that and performance is severely
> affected, two minute render becomes a ten minute render, could a 'Low memory
> - renders will possibly be slower' warning be displayed in the render
> header?

Maybe, but I'm not sure if we have a good way to estimate when
performance will be affected and when not. I'll look into this memory
usage problem further this week.

> Can't find a reason for memory usage increase however so supplied test
> .blend (below).
>
>
> Also noticed. Is it by design that F12 render preview now only updates Power
> of 2 -1 for each consecutive update? This is okay for low sample amounts but
> for renders with a few thousand samples as the render progresses it appears
> nothing is happening or Cycles has frozen and may prompt a user to cancel
> the render.

It's not really by design, but due to the async changes that were done
to avoid a lot of CPU usage. These have now been reverted for the 2.71
release, so that update problem should be gone as well.

Thanks,
Brecht.