[magicalhippo]

Lets be even more abstract. What matters is useful work per second.

That metric is a function of clock speed, core count, lithography process, but also how many cycles each instruction takes to execute (e.g. how many cycles for an add), the instruction level parallelism in each core, branch prediction, memory architecture and caching, instruction set architecture (ISA) and its implementation, available cooling and more.

For example, by optimizing the number of cycles per instruction, increasing instruction level parallelism and branch prediction you can get a significant boost in performance, as witnessed by the massive jump[1] from the 486DX2 66Mhz to the Pentium 60 (also at 66Mhz in the video below).

[1]: https://www.youtube.com/watch?v=NLrKxWL73Mw