AMD and even Intel have reasonable to good performance / watt for most of the curve... But they do let you explore the top side of the curve where you get a little more performance for a lot more power. This is mostly because of how Intel and AMD compete directly and high end performance looks good in reviews.

Few (if any) ARM processors let you do that.

In many (most?) Intel/AMD systems, you can limit the maximum power delivered to the CPU and get good efficiency and most of the possible perfomance.