Activity Monitor only sees one core

[NurkJon]

I know this thread is old but I stumbled over it when looking for another thing, just in case anyone is wondering, the activity monitor won't show more than 4 cores/threads so if you have a Quad Core with Hyper Threading (such as the i7 processor like the 875), a Hexa Core or a Octo core (4+ really) CPU it will only show one bar in activity monitor (the same thing were true for my Mac Pro and all Mac Pros I've seen). However if you press cmd+2 or cmd+3 you should see all 8 cores. You probably already know this by now but in case you didn't or someone else find this thread it's good to provide an answer.

 

[jasonhill1981]

I know this thread is old but I stumbled over it when looking for another thing, just in case anyone is wondering, the activity monitor won't show more than 4 cores/threads so if you have a Quad Core with Hyper Threading (such as the i7 processor like the 875), a Hexa Core or a Octo core (4+ really) CPU it will only show one bar in activity monitor (the same thing were true for my Mac Pro and all Mac Pros I've seen). However if you press cmd+2 or cmd+3 you should see all 8 cores. You probably already know this by now but in case you didn't or someone else find this thread it's good to provide an answer.

Thank you this answered my question...
I'm using a 3770k i7

Open activity Montor then press cmd+3 or double click on the CPU Load graph will bring up another window showing all cores.