According to one YouTuber, Apple has completely altered the way these MacBook Air models behave when running taxing workloads. In one test, the new MacBook utilized the efficiency cores instead of the performance ones, resulting in multiple benefits.

When running Lightroom Classic to edit images, YouTuber Vadim Yuryev, who runs the channel Max Tech, found out that the M4 MacBook Air takes advantage of only the six efficiency cores while the performance cores were barely being touched. Keep in mind that Adobe’s image editing software is extremely CPU-intensive, which makes this behavior all the more surprising because it was always assumed that the performance cores would be responsible for tackling these sorts of tasks.

While no explanation is provided as to why just the efficiency cores are being used, the M4 MacBook Air’s behavior is incredibly different compared to the M3 MacBook Air, where only the latter’s performance cores were being utilized when running Lightroom Classic. Perhaps Apple had intentionally forced the M4’s Neural Engine to recognize which applications can be handled by the efficiency cores without hampering the program’s performance or user experience.

Since Vadim has only shared two images showing the two chipset’s behaviors when under load, it is difficult to ascertain how well Lightroom Classic runs when only the efficiency cores are leveraged. However, assuming the application runs well, this approach is highly beneficial because it will lead to not just better battery life but also better temperatures, minimizing the chances of thermal throttling.

Woah!! Apple’s M4 MacBook Air is pushing this CPU workload to all 6 of the Efficiency cores while the 4 Performance cores are barely being used. (Left photo)

Compare that to the M3 (right) where the 4 Performance cores are seeing a lot more use.

Photo editing in Lightroom Classic pic.twitter.com/y17D8G0ypB

— Vadim Yuryev (@VadimYuryev) March 13, 2025

Source