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As has been mentioned elsewhere, devoting some cores to background tasks and reserving the others for higher-priority stuff also makes the system feel more resp

As has been mentioned elsewhere, devoting some cores to background tasks and reserving the others for higher-priority stuff also makes the system feel more responsive. See, for example, this article from yesterday: https://eclecticlight.co/2021/05/17/how-m1-macs-feel-faster-than-intel-models-its-about-qos/ https://eclecticlight.co/2021/05/17/how-m1-macs-feel-faster-... Long story short, segregating background work from foreground work means that Spotlight indexing won't cause the UI to become sluggish. I'm guessing it also tends to be more cache-friendly.

andrewmunsell 5y ago
But separating the background work doesn't actually require efficiency cores. With 40 performance cores, you could still dedicate 4 or 8 of them to "background" processes only. As that article you linked shows, the background processes would simply complete more quickly without affecting interactive work on the machine.
- karkisuni 5y ago
  performance cores are physically larger than the efficiency ones, by about 3-4x. I'm sure there are other tradeoffs cache size like too. So would you rather have 32 performance cores and 8 efficiency or 34 performance?
- mumblemumble 5y ago
  Consuming 1/10 as much power would also have thermal advantages for the die overall, and segregating them onto a separate L2 cache from the performance cores would help with that cache friendliness situation, different allocations of logic units means you can tailor them toward different kinds of workloads. . . I'm no CPU designer, so I really can't speak with authority here, but I can at least see several possible reasons why it would make sense even when you aren't worried about battery life.
- ksec 5y ago
  In upper end extreme case, using 8 HE Core instead of 8 HP Core saves you 24 to 32W. Those 32W could allow more GPU usage or some other part of system such as ISP or NPU. At the end of the day you will still need HE Core, they just aren't as important comparing to a Battery devices. Not to mention Marketing, Die Size cost consideration.

andrewmunsell 5y ago

But separating the background work doesn't actually require efficiency cores. With 40 performance cores, you could still dedicate 4 or 8 of them to "background" processes only. As that article you linked shows, the background processes would simply complete more quickly without affecting interactive work on the machine.

karkisuni 5y ago
performance cores are physically larger than the efficiency ones, by about 3-4x. I'm sure there are other tradeoffs cache size like too. So would you rather have 32 performance cores and 8 efficiency or 34 performance?
mumblemumble 5y ago
Consuming 1/10 as much power would also have thermal advantages for the die overall, and segregating them onto a separate L2 cache from the performance cores would help with that cache friendliness situation, different allocations of logic units means you can tailor them toward different kinds of workloads. . . I'm no CPU designer, so I really can't speak with authority here, but I can at least see several possible reasons why it would make sense even when you aren't worried about battery life.
ksec 5y ago
In upper end extreme case, using 8 HE Core instead of 8 HP Core saves you 24 to 32W. Those 32W could allow more GPU usage or some other part of system such as ISP or NPU. At the end of the day you will still need HE Core, they just aren't as important comparing to a Battery devices. Not to mention Marketing, Die Size cost consideration.