Seems like the video is being decoded by the CPU which is bottle-necking while encoding with hevc_nvenc. I think given the option to either decode with cuda or QSVenc should translate into way faster trans-coding speeds.
SVPlayer for 🍎 iPhone | iPad | Apple TV and 🤖 Android
SVP 4 for Windows and macOS: 30 days FREE TRIAL.
Read FAQ & follow SVP @ Facebook, Twitter