What makes my computer get hot?

Discussion in 'Mac Basics and Help' started by tekno, Jul 2, 2013.

  1. tekno macrumors 6502a

    Oct 15, 2011
    My (limited) understanding is that it's the CPU.

    But right now my MacBook Air is whirring loudly even though only Chrome, iWeb and Mail is open. The CPU is at 84 degrees (is that normal?) even though usage is 2% User, 1% System, 97% Idle.

    Activity Monitor doesn't appear to show anything unusual.

    So how can I find out why my Mac is so hot and battery life suddenly so bad?
  2. tekno thread starter macrumors 6502a

    Oct 15, 2011
    I'm amazed! Honestly thought someone on here might be able to tell me why my Mac was getting so hot, but I guess that would require some genuine computer knowledge rather than geeky internet knowledge which is probably all that people who frequent forums have.
  3. GGJstudios macrumors Westmere


    May 16, 2008
    I just now saw this thread and was about to answer your question, when I saw this post. If you want to throw a childish temper tantrum and insult forum members who you don't know, simply because they didn't respond to your thread as fast as you wanted, I'm no longer motivated to try to help. You're on your own. I'm sure someone will overlook your rudeness and reply, but I won't waste my time. :rolleyes:
  4. tekno thread starter macrumors 6502a

    Oct 15, 2011
    How ironic that you wasted your time telling me you didn't want to waste your time.
  5. dan1eln1el5en macrumors 6502


    Jan 3, 2012
    Copenhagen, Denmark
    It's the many transistors buried deep inside your CPU and GPU.

    when working = using many if not all, then it uses more electricity.
    When electricity runs through millions of transistors they get hot, because of the resistance in the wire, mind you they are 32 nano meter wide.

    but of course the rest of the system gets hot too, partly from being used and mostly from dispersing heat from the CPU and GPU.

    it's like a light bulb getting hot.

    if you want to know more, then it's the electrons passing by the copper/gold/other rare metals atoms, bumping into them causing them to move about, which is energy = heat.
  6. maxosx macrumors 68020

    Dec 13, 2012
    Southern California
    It's a Mac, they run hot. Just use it, you'll probably be OK.
  7. mentaluproar macrumors 68000


    May 25, 2010
    Ohio, USA
  8. Mr Rabbit macrumors 6502a

    Mr Rabbit

    May 13, 2013
    Chrome is often, in my experience, a processor & memory hog. I rarely use it myself but a good number of my trouble calls involve sluggish performance when Chrome is installed and running. I would switch to Safari or Firefox and consider disabling Flash if the heat bothers you. Also make sure the Mac is on a flat hard surface (not a lap, covers, cushion, etc) and that the keyboard & rear vent aren't obstructed.

    Even then though, what you're describing sounds like pretty normal behavior for the vast majority of Macs. As someone else said, "they run hot" which is absolutely true. It's been that way since the early G4's and I'm sure they'll stay that way for years to come.

    And way to go asking for help then being a tool. So because someone didn't answer you between the evening and 3am you get all pissy and throw a tantrum. Not the best way to win folks over. Calm down, don't check the thread every 20 minutes, come back tomorrow, etc... Not getting a reply in the first 12 hours isn't a valid reason for throwing a fit.
  9. tekno thread starter macrumors 6502a

    Oct 15, 2011
    Well would you look at that - someone did! They were informative, helpful and someone even made a light-hearted comment about dragons. And all without getting personally offended and wasting their time telling everyone. (Thankfully I have tonnes of free time at my disposal)

    You should take a leaf out of their book.
  10. Dave Braine macrumors 68040

    Dave Braine

    Mar 19, 2008
    Warrington, UK
    Wiggly amps.
  11. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    The CPU isn't the only source of heat, though it's the most common. If you're looking for actual troubleshooting, you've mostly ruled out the CPU (Flash is often a hog, but that would show up in Activity Monitor), so the only other possible culprits are GPU or poor airflow due to dust buildup or blocked vents. This is assuming the computer isn't just running at a normal temperature--you didn't say if that was 84C or 84F (84C is rather hot but within spec for the CPU, 84F is very cool). The hard drive and ancillary chips also generate some heat, but in a MacBook Air neither will generate significant amounts.

    I'd offer more detailed help than that narrowing it down to one of those, but a little life lesson, using your free time to disparage the people you're asking for help generally results in less helpful and detailed responses. The correct response to someone pointing that out to you is to apologize for getting worked up unnecessarily, not get irate.

    Kudos to dan1eln1el5en and Mr Rabbit for taking that much extra time to answer after you insulted them, though.

    I love that this answer is, technically, entirely correct.
  12. NewbieCanada macrumors 68030

    Oct 9, 2007
    Being friendless and unemployable will do that.
  13. Apple fanboy macrumors Penryn

    Apple fanboy

    Feb 21, 2012
    Behind the Lens, UK
    GGJstudios is probably one of the most helpful and knowledgable guys on here. He has helped me on a number of occasions. Sometimes you just have to wait for people to respond a little longer than you would have liked.
  14. tekno thread starter macrumors 6502a

    Oct 15, 2011
    That is true. People with no friends and no job would indeed have plenty of spare time.

    In my case I had taken the day off to wait in for the delivery of some furniture. And I've taken today off to spend it with my partner who also has the day off. That's the great thing about owning a company - I can take off as much time as I like.

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