As the title indicates, I have my Activity Monitor dock icon set to CPU History. There are 4 rows of data in the icon. If I switch to CPU Usage, there are 4 bars, but when I look at the CPU section of Activity Monitor, there are only 3 percentages shown: System, User & Idle. Not sure what the 4th one is for & FWIW, the CPU history doesn't seem to correlate with what I see in the actual application, so I wonder if I'm looking at it incorrectly, or making bad assumptions on what the icons represent.
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Activity Monitor Dock Icon CPU Usage or CPU History, what do the 4 bars represent
- Thread starter mk313
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There is variation with version of macOS and model of Mac. Mine is macOS 13 (Ventura) and 2019 iMac (8 core with hyper threading).
CPU History - Dock: The horizontal axis is time, just like the graph on the main CPU window. The two colours represent system (red) and user (green) modes. My Mac shows just one graph as Dock icon. Much the same as graph in main window.
CPU Usage - Dock: Shows current (instantaneous) CPU usage. On my Mac this shows 10 vertically arranged pale blue blobs. The more blobs the higher the CPU usage.
Both the above are condensed views of the CPU History and CPU Usage windows. Show these in Activity Monitor with Menubar > Windows > CLU Usage and CPU History (also Command-2 and Command-3).
CPU History window: CPU History (system and user mode) for each process core - I get 16 graphs from 8 cores with hyper threading. The dock icon is just this condensed to one graph.
CPU Usage window: As many vertically bars as you have CPU cores. Each bar represents the instantaneous usage of each core.
My opinion is that the embellishments of the dock icon are too simplified (and disappear with autohide of my dock). The CPU History Window is much more useful. This window is particularly interesting on an Apple Silicon (M1/M2) Mac as the Macs have two different types of CPU core - performance and efficiency.
CPU History - Dock: The horizontal axis is time, just like the graph on the main CPU window. The two colours represent system (red) and user (green) modes. My Mac shows just one graph as Dock icon. Much the same as graph in main window.
CPU Usage - Dock: Shows current (instantaneous) CPU usage. On my Mac this shows 10 vertically arranged pale blue blobs. The more blobs the higher the CPU usage.
Both the above are condensed views of the CPU History and CPU Usage windows. Show these in Activity Monitor with Menubar > Windows > CLU Usage and CPU History (also Command-2 and Command-3).
CPU History window: CPU History (system and user mode) for each process core - I get 16 graphs from 8 cores with hyper threading. The dock icon is just this condensed to one graph.
CPU Usage window: As many vertically bars as you have CPU cores. Each bar represents the instantaneous usage of each core.
My opinion is that the embellishments of the dock icon are too simplified (and disappear with autohide of my dock). The CPU History Window is much more useful. This window is particularly interesting on an Apple Silicon (M1/M2) Mac as the Macs have two different types of CPU core - performance and efficiency.
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Thanks for the explanation. Interestingly enough, mine shows 4 graphs in CPU historical usage and 4 bars in CPU Usage. I can't find an image that matches the history, but it looks like the first imagine in the following link when set to Usage.
https://osxdaily.com/2012/03/30/watch-system-activity-cpu-usage-mac-os-x-dock/
In reading that article and a couple of others, it might be that each core has a separate bar/graph, but my computer is a 12" Retina MacBook, and the processor is listed as a 1.4 GHz Dual-Core Intel Core i7, so I'd assume that I'd get 2 bars/graphs.
I agree that the actual window is more useful. I was mostly just curious as to why I get what appears to be different info depending on which one I am looking at. Not super important, but was just curious.
Thanks for the detailed explanation.
And I have a MacBook 2015 with an m5 (closer to yours than my iMac). Also dual core and hyperthreading. On that with macOS 12 (Monterey) I see the same as you.
CPU History - Dock: 4 graphs showing System (red) and User (green) mode usage as stacked bars. One graph for each hyperthreaded core (2 cores x 2 for hyperthreading). Horizontal axis - time. Somewhat like the CPU graph in the main window but with each core show separately.
CPU Usage - Dock: 4 vertical bars with pale blue blobs. Instantaneous usage for each of 4 hyperthreaded cores. More blobs for higher usage.
Both those are more informative on my MacBook than my iMac.