V-Ray originally worked with CPU rendering only. GPU CUDA & RTX rendering modes are many orders of magnitude faster than CPU rendering. GPU CUDA & RTX rendering is only supported on Windows PCs with NVIDIA graphics cards.
NVIDIA GTX 950 / 1050 graphics or newer
NVIDIA RTX 2060 / A2000 graphics or newer
AMD Radeon, Apple M chips, and Intel graphics will NOT work with V-Ray GPU rendering modes.