Why do you get CPU usages over 100%?

Discussion in 'Mac Basics and Help' started by Wie Gehts, Jun 2, 2010.

  1. Wie Gehts macrumors 6502

    Joined:
    Mar 22, 2007
    #1
    Whats the trick here? Some kind of computer logic....like how you buy a 500gb hd but its 'really' only 465? How can you get more than a 100% of anything?

    Reminds me of the movie "The Producers" where Max and Leo go to jail for selling investors more than a 100% of their play.

    So how come cpu usage will go, and sometimes waaaay, over a 100%?
     
  2. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #2
    Because with current Macs you have at least two logical cores, thus one core can get 100%, but if you have a process accessing two cores, it can get more than 100%.


    Hard Drive Size Discrepancy

    Why does my new 500 GB hard drive report it only has 465 GB? Have I been ripped off?

    No, you haven't been ripped off. 500 GB = 465 GB, strange as it seems.

    The reason is that computers count a "kilo" something as 1024 (binary 2^10) while the rest of the world count a "kilo" as 1000 (decimal 10^3). A 'mega' in computer binary system is 1024 x 1024 = 1,048,576 (rather than decimal 1,000,000), and a 'giga' is 1024 x 1024 x 1024 = 1,073,741,824 rather than decimal 1,000,000,000

    This creates a discrepancy of approximately 7% between the number of GB the computer reports, and what is advertised as the drive's capacity in GB. It is important to note that there is no difference in the number of actual bytes of storage - it is only a difference in reporting when the binary 'giga' terminology is used.

    A 500 GB hard drive has about 500,000,000,000 bytes (it is never exact, commonly a drive is designed to have more bytes, to allow for a certain number of defective sectors to be mapped out). When counted on the computer, 500 Gb (decimal) = 500 billion bytes = 465.66 GB (binary).

    Some propose using a different term, gibibyte (GiB) for the binary figure, however that is unlikely to catch on in the marketplace.


    from http://guides.macrumors.com/Hard_Drive_Size_Discrepancy
     
  3. Wie Gehts thread starter macrumors 6502

    Joined:
    Mar 22, 2007
    #3
    ahhhh, why didn't I see that. I can't think outside the box!

    thanks :)
     
  4. sammich macrumors 601

    sammich

    Joined:
    Sep 26, 2006
    Location:
    Sarcasmville.
    #4
    Logical yes, but more correctly physical cores.

    Each 'core' is like a processor/CPU. The utilisation of one of these cores is out of 100%. So if you have more than one, you will have >100%. This representation is less ambiguous than the whole computer out of 100%.
     

Share This Page