GPU scaling not as expected with Vray vs Redshift

[Moriah]

@Bigguns

Hey Moriah,
As Vlado mentioned RT GPU should scale pretty linearly. The last time we tested with 8 GPUs it was 7.94 times faster.
So this definitely seems as a problem that I would definitely like to fix.

There is a slightly chance for this to be related with the setup. I know that it is a simple scene, but can you share it anyway ?
Few more questions is which exact version of V-Ray have you tested (there are multiple nightly builds …), and do you use RT GPU as Production or as Active Shade ?
What are your ray bundle size and rays per pixel settings ? As a matter of fact, if you just send the scene over we will figure all this from it Also, did you tested Redshift with bucket or progressive ?

Thanks,
Best,
Blago.

Sure i can share it but only tomorrow i’m off work now. (scene only has vray sun, GI, 1 chrome mat and 1 default vraymat)
Vray i installed yesterday’s nightly build so 3.45.01 june 22nd. Vray GPU as Production. Bundle size and rays per pixel are default settings.
I did test RS in bucket mode (progressive is not really advised there), and tried to have similar settings with vray.

I can also try and see if i can see you the scene where i had the initial issue with scaling, from 30min 3 gpus to 50min 1 gpu, i’ll see if that’s possible.

I don’t know if it’s related to hardware but here goes (recent workstation)

i7 6850K OC to 4.6
32GB DDR4
3x 980Ti 6gb
ASUS X99-E WS 3.1
Windows 10
3dsmax 2015