I have my new MacBook Pro with 2 cores.

However, the Activity Monitor shows me 4 “virtual” cores. (I don’t really know what a “virtual core” is.)

If the processor is running at maximum, what percentages for processes would I have in Activity Monitor ?

  • A total of 200 % ?
  • A total of 400 % ?
  • @grgarside — Related question, but not a duplicate. It seems that the answer by Jake I got here is rather an answer for the other question. Commented Dec 1, 2013 at 20:55
  • Ok, I've retracted my close vote and posted a direct answer. Is there a reason for your rollback of my edit embedding the screenshots?
    – grg
    Commented Dec 1, 2013 at 21:05
  • @grgarside — I prefer to leave the images as links, they are less parasitic this way (the message is kept to the point), they are really not essential to the understanding of my message. Furthermore, there were accessibility problems in their embedding code and their site was not reliable. Commented Dec 1, 2013 at 21:20

2 Answers 2


The CPU percentages shown in Activity Monitor are 100% for each virtual core.

Therefore, for your hyper-threaded dual-core processor, 400% is 100%.

In my case, the hyper-threaded quad-core in my Mac means that 800% is 100%.


The answer—as explained here—is because of hyperthreading. 1 CPU with 2 cores and 4 virtual cores. Your MacBook Pro (Mid 2012)—as per the screenshot that ids it as “MacBookPro 9,2”—uses a 2.9GHz dual-core Intel Core i7 processor. The i5 & i7 processors use hyperthreading.

EDIT CPU percentage on multi-core systems is 100% multiplied by the number of cores. If you have 4 cores, your CPU running at max will be 400%.

  • So ? What is the answer ? Commented Dec 1, 2013 at 20:56
  • Your answer contradicts what @grgarside says. I think grgarside is right. Commented Feb 19, 2014 at 21:21

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .