Assassins Creed is a terribly optimized game, one of the reasons it's so often used in benchmarks, it's brutal on a cpu's ability to put up fps. Far Cry 5 and Witcher 3 are also hard on a cpu and are all 3 are optimized for 8 thread usage so are really hard on quad cores. With all that weight packed onto 4 thread quads, anything that affects performance will be even larger. Just 1 setting out of place can have disastrous results.
There are also videos out on settings to use for getting better performance for specific games, but don't make the assumption everything is the same. So far you mention just the cpu/gpu. There's no mention of the videos using NVMe drives with the games instead of Sata or hdd. Is the pagefile set on hdd, or ssd, is it a low performance ssd or a Samsung Pro. There's many things that'll affect total fps output that those videos don't explain, aren't forthcoming with etc.