You'd need to run them on the same machine to make sure you get a proper comparison but https://ffmpeg.zeranoe.com/forum/viewtopic.php?t=5601 has some runs. One of the users downthread ("entac") provides both libaom and libx264 numbers, they get 63fps for libx264 and 0.0924fps for libaom (r9028)

Also this currently does delegates work to libaom.