hello everyone, I have 4 video cards but I would like to use only 1 specific card at the time of rendering/interface I would like to know how do I change

using houdini version 18.5

Don't Know if this will help you, but try this?

HOUDINI_OCL_VENDOR = NVIDIA Corporation
HOUDINI_OCL_DEVICENUMBER = 1 # If you have 4 GPUs start with 0-3