In the end it's not the frequencies nor number of cores but performance per watt that matters. Most computers run on batteries these days, and those that don't

In the end it's not the frequencies nor number of cores but performance per watt that matters. Most computers run on batteries these days, and those that don't drain ever more expensive electricity from the wall socket and at the same time waste a lot of it producing huge amounts of heat. The more you get out of a watt the better. You can either trade in speed for lower power or trade in power for better performance, but in either case you want the performance/watt ratio to be the highest. I would guess the power consumption of running the chip at 5GHz is pretty high. And running temperatures as well. And yet there are fewer and fewer of those huge tasks that you can only do with one core.