V-Ray originally worked with CPU rendering only. GPU CUDA & RTX rendering modes are many orders of magnitude faster than the CPU mode, but they are ONLY available on Windows PCs with NVIDIA model graphics in them.
NVIDIA GTX 950 / 1050 graphics or newer
NVIDIA RTX 2060 / A2000 graphics or newer
AMD Radeon, Apple M1/M2 and Intel graphics will NOT work with V-Ray GPU OR V-Ray RTX modes.