Mountain Lion running hot?

Discussion in 'OS X Mountain Lion (10.8)' started by Paulyboy, Jul 28, 2012.

  1. Paulyboy, Jul 28, 2012
    Last edited: Jul 28, 2012

    macrumors 6502

    Jan 26, 2007
    Has anybody noticed an increase in their CPU temperature since installing Mountain Lion? It seems like mine runs at least 5° hotter (and sometimes even more) since I installed Mountain Lion on launch day. For example right now my CPU is running at 52°C, which isn't anything to be concerned about I realize, but it's still at least 5° hotter than it would normally be right now.

    Anybody else notice a difference?

  2. macrumors newbie


    Jul 27, 2012
    It's running hotter for me too. Perhaps it might be addressed in a future patch.

    See attached.

    Attached Files:

  3. macrumors newbie

    Dec 22, 2008
    I noticed that sometimes some applications (Safari, Mail, Finder) take a significant amount of CPU % (up to 10%) when doing nothing. This, in turn, has an effect on the whole machine temperature. Restarting them (and, in the case of Safari, going back to the page that was open before) brings them back to 1-2% of CPU and the machine cools down. Weird.
  4. macrumors member

    Jan 15, 2008
    yeah my macbook is burning up running it. Not keen on this!
  5. macrumors newbie


    Jul 28, 2012
  6. macrumors 65816


    Nov 17, 2010
    Macbook air and i'm getting cooler temps and longer battery life.

    simple browsing i'm chilling at 55ºc

    used to be 60'ish
  7. JGO
    macrumors member

    Feb 24, 2009
    My 2009 MBP is noticeably hotter, especially when charing, and the fun runs more than it did with 10.7

    I haven't taken the time to check the temps, but I have checked activity monitor and did not see anything unusual about any of the active processes.
  8. macrumors 6502a


    Jul 13, 2008
    Jersey, Channel Islands
    I've found that my Mac runs hotter than before using the dedicated graphics, but actually cooler when using the integrated graphics. A little strange.
  9. macrumors 6502a


    Feb 4, 2010
    Yes, I'm noticing it's running a little warmer than usual.
  10. macrumors 6502a

    Mar 24, 2011
    2011 base 13" MBA. Seems a bit cooler for me.
  11. macrumors 6502

    Dec 26, 2009
    Before ML my CPU would run at about 50 degrees C with Chrome open, now it can hit anywhere between 60 and 80 degrees C. ML definitely runs hotter than Snow Leopard.
  12. chilady1, Jul 28, 2012
    Last edited: Jul 30, 2012

    macrumors member


    Dec 29, 2011
    Same here - prior to ML install, almost NEVER heard the fan unless I had a few apps open. Now, it seems like the thing is running all the time. I do have a Speck Clear Case on my MBP 13 and experiementing right now with removing that to see if that helps with the heat.

    I thought it might just be me but seems like others are noticing the same thing. I have checked out my Activity Monitor and nothing out of the ordinary appears to be occurring. Hope a patch is on the way to address this.

    7/30/12 Update: Turns out I solved my problem. I had a process called bash running and I really didn't think much of it at the time because it was only using about 6-7% of the CPU. On the Apple Community forum I found a thread where someone indicated that this "bash" process was hosing up their CPU even though the number wasn't high like 99%. This process is associated with Send to Kindle for Mac which I had on my computer.

    I removed this app and just like that - my temp went from 88-90C to a steady 45C and my RPMs went from 4500-5000 to a steady 2500. I am so glad that I found out what was causing this issue and now, my baby is back to the way it was before. Just wanted to pass this information on in the event it might help someone else.
  13. macrumors newbie

    Jul 28, 2012
    Well same here! i just changed cpu thermal compound on my MBP 13 mid 2010 3 days ago while i had Lion, and my idle temps were 40-45 C even 38 C, and today installed Mountain Lion and now is running hot, idle 50-55, that isn't good. now i cant have it on my lap for a long time without sweat! :D haha. i hope they fix this soon!
  14. macrumors newbie

    Jul 28, 2012
    I'm noticing the CPU temperature increase on my MBP 2010 as well. It went from <43C to >50C (when idle). And I think this increases the battery drain because the notbook doesn't last as long as it used to when I was running Snow Leopard on it.
  15. macrumors newbie

    May 27, 2004
    Mackbook 5,1 (ie, 2009)

    Definitely running hotter. No doubt about it. Just sitting idle with all the apps closed and the fan will kick on. Previously, the fan almost never ran. 52C at the moment with only Safari and dashboard running.
  16. macrumors member


    Oct 18, 2011
    Foster City, CA
    stupid question

    I know this is a stupid question, but how do you check the cpu temperature?
  17. macrumors newbie

    May 27, 2004
    Download the iStat widget for your dashboard.
  18. macrumors member


    Oct 18, 2011
    Foster City, CA
  19. macrumors 6502

    Apr 30, 2012
    I bought Mountain Lion on a few days ago and yesterday since the first time that I bought my MacBook Pro in the beginning of the year had it not once shut down on its own from heat, before it shut down it was constantly going 65+ until it just shut down! I feel like putting back Lion. This is a 2009 unibody model.
  20. macrumors regular


    Dec 16, 2010
    Even with a few apps and a single vm running, I am running between 75ºc and 95ºc constantly. The only time it gets cooler is when I first start it up, then bam, right to 75ºc it goes and stays there until I start up more apps and vm's and the fans kick in until it gets back under 99ºc.

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