People are getting their hands on the new M4 MacBook Air this week, which means they’re posting lots of discoveries about its performance (and the blueness of the new Sky Blue color). While editing photos in Lightroom Classic, YouTuber Vadim Yuryev noticed that the CPU workload was being handled almost completely by the laptop’s six efficiency cores.
Woah!! Apple’s M4 MacBook Air is pushing this CPU workload to all 6 of the Efficiency cores while the 4 Perfomance cores are barely being used. (Left photo)
Compare that to the M3 (right) where the 4 Perfomance cores are seeing a lot more use.
Photo editing in Lightroom Classic pic.twitter.com/y17D8G0ypB
— Vadim Yuryev (@VadimYuryev) March 13, 2025
Spotted by Wccftech, this behavior is interesting because the image editing software is so CPU-intensive that anyone would assume it needed the performance cores to run. This was certainly the case for the M3 MacBook Air, which Yuryev shows using all four performance and all four efficiency cores to get the work done.
We don’t know why this behavior has changed, how purposeful it is, or if it’s specific to Lightroom Classic — but the benefits could be significant. Keeping the efficiency cores busy and limiting the activity on the performance cores could improve battery life and keep temperatures down.
That said, we don’t know from Yuryev’s post how well the software is running while in this state — we can assume he’s pointing it out because it’s running fine but we don’t know for sure.
It’s also not entirely impossible that this is a bug of some kind — the performance cores are there to be used, after all, or else they’d be pointless. So the sheer amount of activity on the efficiency cores while the performance cores sit almost unused does seem quite odd.
With outlets like Wccftech and tech influencers everywhere experimenting with this new model, we’ll likely find out soon whether this was a fluke or an intended feature of the new MacBook Air.