Hi everyone,
As in Modo’s “Select OpenCL devices for V-Ray RT” tool to select which GPUs are enabled, I’d like to know if there’s a similar option for Blender to know which GPUs the system is using. Or does it use all the ones it finds by default?
regards,
Alvaro
Well, I found it out via trial/error. It turns out that indeed the “Select OpenCL devices for V-Ray RT” utility sets the cards you want to use/disable not only in Modo but also in Blender (or I guess it sets the cards to use globally). I tried it out setting 1 card only, then 2 and monitored the GPU temperature. Also, when setting the 2 cards render times are cut in half.
What I don’t know is if such utility comes with the standalone installation. Can someone please confirm?
regards,
Alvaro
Yes, that utility program is installed with the standalone in the tools folder.
Thanks Andy. 
I’m glad the utility’s there. I had the idea it was only available with other Vray versions.
Regards,
Alvaro
Hi Guys,
Since I now updated to VRay 3.6 I am trying to implement the new hybrid rendering feature. In another thread I was told by bdancer to use the ocldeviceselect.exe to set up for rendering with both GPU and CPU. So I did that and marked all my devices and clicked the “Set devices” button. Then I have tested to see what happens when I use GPU rendering in VRay Blender and I still get “out of memory errors”. My videocard has 2GB Ram (NVidia CUDA) and the CPU is using 32GB Ram so it appears as if it is only trying to use the video card memory still.
I also noticed in the console window some lines that say that certain devices are not connected to NVlink or something, which is also a new thing in 3.6, so maby that needs to be set up as well.
If anybody can point me out what I need to do to get it to work I’d appreciate it. Andybot, you’re the man around here when it comes to GPU rendering so I hope to learn a lot from you 
Btw, after clicking the “Set devices” button it says “The change will take effect the next time the VRay RT render server runs” Do I need to run it from somewhere specifically or does it run automatically when you try to render something with GPU rendering in Blender?
Thanks and happy rendering!
@Txeroki Lol, I hope to learn a lot too. It’s August, I just got back from vacation. I’m looking forward to jumping on the 3.6 wagon, I’ll let you know what I find
Thanks, I look forward to it!
For the time being there is no difference for me between 3.5 and 3.6 since the new feature of Hybrid rendering apparently does not share memory between GPU and CPU, only processing power, so I cannot render anything with over 2GB of memory in the scene.
Good luck with your investigations!