P cores are conventional in that they can deliver excellent performance at maximum frequency, but with high power use. E cores may take 4 times as long for a task, but use less than a third of the energy.
Activity Monitor
How to interpret various measurements reported in Activity Monitor, from % CPU to Energy Impact, and how they can be compared across different Macs.
All about memory: different types, Unified Memory, Mach zones and the kernel, and how to manage system memory problems.
What to do with the Mac that either won’t go to sleep at all, or keeps waking up and discharging its battery? It’s pmset or Sleep Aid.
Using a test of compressing a 1 GB file with AppleArchive, measurements of power used by core clusters show how efficient using the E cores really is.
Using CPU % or Energy values in Activity Monitor appears to show that running code on E cores is less efficient than on P cores. Don’t believe a word of it.
How can you tell how much memory is being used by the GPU when both CPU and GPU use Unified Memory? Does it matter anyway?
Current CPU % given in Activity Monitor can be misleading and has limited value for M1 models. Here’s how to improve it.
In Activity Monitor, % CPU isn’t on a scale of 0-100. In M1 Macs, it also makes no distinction between E and P cores, nor does it allow for their changing frequency.
Activity Monitor’s Memory view is the perfect place to watch for memory problems, such as a leak. Demonstrated here in macOS 12.0.1 and 12.1.
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