Does that matter on a laptop? My thick laptop thermal throttles if I take advantage of all of its 8 cores, lowering clock speed to 75% or 50% depending on the power setting.
Having a good number of efficiency cores is useful on a laptop because they can do more work in the same thermal envelope when throttled.
Yup.
I just checked on my 16" i9-13900HX (8P+16E cores) laptop.
With the lid closed and running in "balanced" mode — hitting Fn-q cycles between economy (2.2GHz fixed), balanced, and performance modes — and compiling a Linux amd64 defconfig kernel, the P cores are running at
3.8 GHz first 30 seconds
3.0 GHz until 65 seconds
5.4 GHz doing linking and stuff until finished at 76 seconds
In Performance mode:
4.5 GHz first 10 seconds
4.4 GHz until 20 seconds
4.2 GHz until 26 seconds
4.1 GHz until 38 seconds
4.0 GHz until 43 seconds
3.9 GHz until 46 seconds
3.6 GHz until 53 seconds
5.4 GHz until finished at 64 seconds
It's a LOT louder. My phone with an app, sitting between me and the centre of the front edge of the computer says says a maximum of 47 dBA in performance mode vs 42 dBA in balanced mode against 30 dBA in this room when it's at idle (and with my Pecron E3600LFP quietly humming away taking in solar power about 3m from me ... it gets to 42 dBA for a few minutes from time to time when the fans crank up a bit).
In economy mode it's just a flat 2.2GHz and 30 dBA indistinguishable from idle sound output for the whole 130 seconds of the build. And uses a LOT less battery if you're on battery.
Note: when my aircon cycles on, on the opposite side of the room, that's 48 dBA.
More notes: what internet has to say about sound levels...
High Concentration / Deep Focus: 35 to 40 dBA (similar to a quiet library or soft hum).
General Office Work / Routine Tasks: 45 to 55 dBA (comparable to a quiet suburban home or background refrigerator hum).
Collaborative Areas / Open-Plan Buzz: 50 to 60 dBA (similar to quiet background conversation)
Legal limit in NZ without the employer providing hearing protection: 85 dBA averaged over an 8 hour shift. Holy shift!
All measurements made with the free "Decibel X" app on an iPhone SE 2022.