Eyballing die shots, Firestorm is about 4 times the size of Icestorm, so if you have perfectly parallelizable workloads, you stand to gain if Firestorm is less

Eyballing die shots, Firestorm is about 4 times the size of Icestorm, so if you have perfectly parallelizable workloads, you stand to gain if Firestorm is less than 4 times as fast per core. (This ignores L2 cache and maybe some other supporting transistors which makes things much more complicated.) In the simple benchmarks, the speed differences range roughly from 2x to 5x. It looks like the current configuration (4 Firestorm + 4 Icestorm) is pretty well balanced: equisized alternatives (5 Firestorm + 0 Icestorm, or 3 Firestorm + 8 Icestorm) can be faster for specific workloads, but probably not across the board. The Apple CPU team really knows what they're doing (but that has been abundantly clear for many years now).