The face-recognition algorithms will make use of NVidia GPU resource if you have it available.  If you are building a real-time face-recognition or analysing lots of image and video data then it is recommended that you use a GPU.    


The GPU has to be an NVIDIA® GPU with Kepler, Maxwell or Pascal architecture, with 4GB VRAM and 640 cores (e.g. GTX 1050) with latest NVIDIA drivers installed.