Even if you have several graphics cards in your system, only one is considered as the main OpenGL or Direct3D device. For OpenCL and CUDA, GPU Caps Viewer details the API support of each capable device available in the system. GPU Caps Viewer offers also a simple GPU monitoring facility (clock speed, temperature, GPU usage, fan speed) for NVIDIA GeForce and AMD Radeon based graphics cards.
GPU Caps Viewer 1.15.1 changelog