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question about Activity Monitor CPU Usage cores
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Jun 25, 2013, 10:14 PM
So Activity monitor measures CPU Usage in a nifty little rolling series of green and red dots piled on top of each other to measure the amount of CPU usage. It looks a little bit like a stock ticker.

On systems with more than one core, it has one of these CPU usage graphs for each core.

See: OS X: Activity Monitor shows one CPU Usage graph on systems with more than four cores

But my 15" rMBP i7 with 4 cores only shows one graph in the activity monitor.
And my 11" MBA i7 with 2 cores shows four graphs in the activity monitor.

Can anyone explain to me what is the reason for this discrepancy? Thanks!
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Jun 26, 2013, 05:20 AM
Both your Macs have Hyperthreading, a feature that makes each processor core appear as two to the operating system. To the operating system, your 11" MBA has 4 cores and your MBP has 8. Presumably Activity Monitor defaults to only showing one graph when you have 8 cores, because it would confusing otherwise. There's probably a setting to override it in one of the menus.
The new Mac Pro has up to 30 MB of cache inside the processor itself. That's more than the HD in my first Mac. Somehow I'm still running out of space.
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Jun 26, 2013, 08:33 AM
Ah, ha. THX!!!
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Jun 28, 2013, 04:34 AM
My 8 core Xserve shows all 8 cores.
I have plenty of more important things to do, if only I could bring myself to do them....
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