A faster and more power hungry SoC can finish the task with better work done per joule if it is fast enough to offset the extra power consumption. It is my understanding that this is often not the case. See e.g efficiency cores compared to performance cores in these heterogeneous design; the E cores can get more done per joule AFAIU. If my understanding is correct, then removing the P cores from the M4 chip would let it get more work done per joule.
Regardless, the environmental impact I'm thinking about isn't mainly power consumption.
I don't know the details of iOS's scheduler or how it decides which tasks should go on which kind of core, but the idea is to put tasks which benefit from high performance on the P-cores, right?
Regardless, the environmental impact I'm thinking about isn't mainly power consumption.