V-Ray's "Low GPU Thread Priority" doesn't seem to be working correctly

V-Ray V-Ray GPU Issues
1

I just added a second card to my system and wanted to test V-Ray’s “Low GPU Thread Priority”. It doesn’t appear to be working as advertised. As far as I understand, it’s only meant to slow down the gpu plugged into the monitor.

I ran some quick benchmarks using RT GPU in MODO.


Monitor 1: 670
Monitor 2: 670
Nvidia Control panel: CUDA = ALL, OPENGL = 670

1080ti                      0m57.8s
1080ti + CPU                0m53.1s
1080ti + 670                0m44.6s
1080ti + 670 + CPU          0m42.2s
1080ti + 670 + CPU + LP     1m59.8s

The last benchmark with low GPU priority (LP) should be about the same as “1080ti + CPU”, but its slower than everything. In this setup, only the 670 (plugged into monitor) should be slowing down.

EDIT: And before anyone mentions it… I obviously wouldn’t render with this setup because I’d limit everything to the 670’s 2GB of VRAM. I’m just pointing out the problem in the “low gpu priority” feature

2

Hey, Funk,

Thank you for the feedback. I am able to reproduce the behavior with V-Ray for Modo 3.60.01, so I’m going to log it. Keep you posted on it.

Cheers,