In Activity Monitor, is the percentage out of each core or out of each virtual core?

Question

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 % ?

Answer 1

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%.

Answer 2

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%.