I'm trying to render a cycles scene. On a computer with an RX480 card it renders fine with (almost) 100% GPU utilization. The exact same scene is rendered slower on a computer with 8 (!) Titan-X GPUs . GPU-Z reports almost no utilization on those GPUs, somewhere between 0 and 2%.
Initially I had the same problem with the RX480. I played around a bit with the settings and suddenly Blender was reloading the render kernels and then everything worked. It seems I am not able to force blender on the Titan machine to do the same?
I tried to disable all but 1 GPU on the Titan machine but it didnt change a thing: Rendering time is the same, utilization on all GPUs the same. (Which makes me think that the GPUs are not really rendering anything)
I downloaded the benchmark scene with the 2 BMWs and got a rendering time of about 3:27, GPU utilization still below 5%.
Is there a way to force a render kernel reload/recompile? Are there any other options I could try?
One last thing: The Tesla machine is accesed via RDP session (windows 10 x64) which means I had to put an opengl32.dll file into the installation directory to allow Blender to start in legacy mode. While this makes Blender itself reaaaally slow, I dont think it should impact CUDA performance in any way.
I am using Blender 2.79 RC2 on both machines.
I would upload the Scene, however it is almost 300MB in size due to some funny dude (me) applying all the modifiers.