I have to agree with NVENC. I've benchmarked dozens of HW and SW encoders for quality (not just encoding speed) and it gives the best BD-Rate on average. For

I have to agree with NVENC. I've benchmarked dozens of HW and SW encoders for quality (not just encoding speed) and it gives the best BD-Rate on average. For H.264, hardware can brute-force every possible Intra encoded macroblock and make rate-distortion-optimised QP/prediction decisions in real-time or better. This gets much harder for H.265, where brute-force is fairly impractical and the clever algorithm wins. A well-designed hardware codec can also run inter-frame block matching searches vastly more efficiently than software can.