Discussion in 'MacBook Pro' started by Hughm, Oct 10, 2012.

  1. Hughm macrumors member

    Dec 12, 2009
    IstatPro shows my CPU running at 50+ degrees C most of the time.

    Is this normal?
  2. SlickShoes, Oct 10, 2012
    Last edited: Oct 10, 2012

    SlickShoes macrumors 6502a

    Jan 24, 2011
    Deleting my brain fart of a response.
  3. sweetbrat macrumors 65816


    Jun 17, 2009
    Redford, MI
    I'm not sure where you got those numbers from, but they're not correct. 50C is perfectly fine. If under heavy load, the CPU can easily get up over 90C and that's fine, too. The computer will shut down if it overheats, but that won't kick in until about 100C.
  4. snaky69 macrumors 603

    Mar 14, 2008
    I hope you're being sarcastic, else that was the most misinformed post I've read in a long time.

    Mobile chips can withstand up to around 105C before shutdown, 50C is nothing at all to be worried about, move along now.

    OP, search the forums for the thousands of thread on the very same subject available on this forum, your computer is perfectly normal, quit looking at your temps and worrying.
  5. Interstella5555 macrumors 603


    Jun 30, 2008
    While you're correct that the computer will shut off if it gets too hot, you're underestimating it's tolerance levels by about 50c. Unless you're kidding which I can't really determine....
  6. Queen6 macrumors 604


    Dec 11, 2008
    Land of the Unexpected
    Your temps are fine and very similar to my own Retina, Late 2011 2.4 i7 15" Unibody & Early 2008 2.4 C2D 15" Classic; If you are concerned about temperature and want to reduce it elevation of the rear of the machine helps, as sitting flat on the desk only reflects the heat back to the base of the Mac. You can buy passive aluminium coolers like Rain Designs Mstand or iLap. Most powered coolers are designed for PC notebooks and don't work overly well with Mac`s if at all. One cooler that does work efficiently is the Moshi Zefyr 2, as it`s principle of cooling is specifically designed for Apple portables, by blowing the air horizontally across the base of the computer, however don't expect miracles.

    Link: Moshi Zefyr 2
    A cheap USB fan can achieve the same if strategically placed, not as elegant mind, nor as easy to put in your notebooks case :p but they do help to reduce case temperatures.

    You can use software to override Apple`s own cooling algorithm by manually taking control of fan RPM and setting up power profile presets with SMC Fan Control 2.4, or here with UltraFan which allows you stipulate a preset temperature and the software will automatically raise and lower fan RPM`s to keep the system at the predefined temp, which i personally feel is a far more elegant solution. At the end of the day you want to control your system temperature, not your fan rpm`s. For me SMC is now pretty much redundant with the latest release of UltraFan having manual control of the fans RPM, and subsequently i am starting to uninstall it from my own Mac`s. SMC FC is a great app, however although it`s recently updated, functionality is limited compared to some newer apps, equally SMC Fan Control is rock steady stable and a finished product.

    Strictly speaking Apple`s own cooling algorithm works, albeit at sacrifice of increased temps for quieter operation. This has always been the Apple way and is really nothing detrimental to the system, i have one MBP from 2008 all original barring a recent fan change that has an uptime of over 30K hours. The latest MBP`s need less assistance in remaining cool; for some it`s simply disconcerting the heat generated and transferred to the case, although it`s perfectly normal as the aluminium acts as a heat-sync. i have to deal with elevated ambient temperature so at times a software solution is useful. Apart from the passive cooling the Mstands bring they also offer a very sound ergonomic solution. A passive cooler and UltraFan will maximise the cooling, there is little else you can do short of reducing the ambient temperature or the system load. If I know i am going to push a system i will close all apps that are not essential as this can and does make an impact to system temperature.

    High temperatures in general is not overly harmful to your systems, what is far more detrimental is thermal stress, where temperatures rapidly fluctuate by significant margins over a short period of time. Anyone striving for great longevity should look to minimise rapid temperature changes, here UltraFan is your best friend.

    Using a RainDesign Mstand, a Moshi Zefyr 2 and latest version of UltraFan I can reduce temperature by over 20C when transcoding an MKV video file, and that is something worth thinking about;

    • Apple default cooling algorithm 99C - 103C (still on Mstand) fans 4K and escalating :eek:
    • Mstand, Zefyr & UltraFan 79C - 82C fans at 5.8K :cool:

    The old adage still applies; it`s easier to keep a system cool, than cool-down an already hot machine. This being said it`s not strictly necessary, equally it`s nice to know that there are options for reducing temperature out there.
  7. GGJstudios macrumors Westmere


    May 16, 2008
    Yes, it's normal. Read below.
    That's not true. 50C is quite normal. The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C (221F), GPU Tjmax = 100C (212F) on i3, i5, i7 processors. (Source: Intel)

    If you're not already using it, iStat Pro (free) or iStat Menus ($16) will give you accurate readings of your temps and fan speeds, among other things.

    Unless there is a rare defect in a Mac, most temps are well within the normal operating range, considering the workload being put on it. Websites with Flash content, games and other multimedia apps will put higher demand on the CPU/GPU, generating more heat. This is normal. If you're constantly putting high demands on your system, such as gaming or other multimedia tasks, expect temps to rise and fans to spin up accordingly. It's just your Mac doing its job to maintain temps within the normal range.

    It is also quite normal for your Mac to become extremely hot to the touch during intensive operations. The aluminum body transfers heat more effectively than other materials used in computer casings, so you will feel the heat more. This doesn't indicate that it's overheating and will not harm the computer to be hot to the touch.

    Your fans are always on when your Mac is on, spinning at a minimum of 2000 rpm (for MBPs) or 1800 rpm (for MBAs, MBs and minis). iMacs have 3 fans with minimum speeds in the 800-1200 range. They will spin faster as needed to keep temps at a safe level.

    If your fans are spinning up without increased heat, try resetting the SMC.
    (PRAM/NVRAM has nothing to do with these issues, so resetting it will not help.)

    The intake and exhaust vents are in the back of the computer near the hinge on all Mac notebooks (except the new MBP with retina display, which has intake vents along the sides at the bottom). The iMac vent is a slot on the back near the top of the computer. Make sure the vents remain unblocked to allow your computer to perform at its best.

    Learn about the fans in your Mac
    Apple Portables: Operating temperature

    For Flash-related issues:
  8. SlickShoes macrumors 6502a

    Jan 24, 2011
    Yes, I read what I wrote, it was a total brain fart. I have no idea why I did that as I am aware the temperatures are fine and check mine regularly and see temps much higher than he posted.

    brain fart.

  9. thermodynamic Suspended


    May 3, 2009
    Assuming it does kick in. There were reports of 2010 MBPs that got to 105C and they didn't shut down... maybe they lacked the power function override...

    It's the same Intel CPU found in any ol' laptop, and they don't always shut down... There was a (Sandy Bridge-based) Dell that got fried despite the assurance of "it will shut down on its own, the temp is A-OK, etc").

    Even if it does, since the fans will shut down right along with it, and with the pesky laws of physics prevailing, the level of heat pent up will still likely damage the CPU -- or reduce its lifespan.

    Just because a CPU can run at x degrees C does not mean it should.

    A GOOD design prevents temps from getting that hot in the first place. It's that simple.

    Mine idles at 35C in a room that's around 20C. When under full load, it gets into the 90s. It typically hovers in the 40s, but gets into the low-60s during app installs or during Photoshop use (typically high-50s). All of those are great temps.

    I will not render, or do anything that gets the CPU over 85C. Not for more than 15 minutes or so, and I use SMCFanControl to up the fans to full.

    Especially with smaller CPUs using smaller electricity paths (22nm, etc), electromigration can become an issue and heat worsens the potential for premature failure. Any Sandy Bridge overclocking forum will go more into detail, but both heat and overvolting (the latter can't be done on Macs, thankfully) are both very legitimate concerns.


    I have to disagree with that.

    Even googling "aluminum vs plastic insulator" will reveal the same things: Aluminum is, by far, the better insulator - meaning it's trapping air and keeping the innards hotter. Plastic is porous (and leeches chemicals into liquids, which is why I don't care for plastic drink containers, but I digress). Being porous means the thing can 'breathe' - hot air escapes more effectively than the (near-nonexistent) air channel inside the MBP's chassis (the 2012 rMBP purportedly rectifies this, but I've yet to use one... would love to buy one since I've practical uses for it too, but not for a while...)

    I had a 2010 Sony quad core laptop that never got above 76C. It was plastic junk. The finely designed aluminum 2009 MBP got to 98C when compiling code. Aluminum transfers heat only when in direct contact. These things are not gigantic heatsinks, otherwise we wouldn't see news article after news article of high temperature problems.

    Even users replacing the gobs of (clearly low-quality) thermal grease with proper quantities of good grease (e.g. Arctic Silver, or others) have seen a 10C drop (my2011macbookpro.com, ifixit).

    These things are not ideally designed based on temperatures under load, and plenty of articles are very telling in that they are not well made. Not for the prices being commanded.

    But that is a myth, which I used to believe when I first bought mine and until I saw the temperatures speak for themselves, that aluminum channels out hot air. It doesn't. It is not a heatsink, for it is not attached to the heat-generating elements (CPU, GPU, northbridge, etc). It therefore acts as an insulator.

    Physics and reality - I hate them too.
  10. GGJstudios macrumors Westmere


    May 16, 2008
    "Breathing" is not required to transfer heat, and no air is being transferred through either aluminum or plastic. Aluminum conducts heat very effectively.

    ScreenCap 2012-10-10 at Wed, Oct 10,5.01.45 PM .PNG
    Source: http://www.sciencecompanion.com/wp-content/uploads/2009/01/sample_energy_srb_pp_57-67.pdf
  11. GermanyChris macrumors 601


    Jul 3, 2011
    Please remember that here (MR) anything that doesn't shut the computer down is A OK..

    My 17" (C2D) was idling at 52C so while I was replacing the HD last week I cleaned and reapplied thermal paste. The computer now idles in the 30's and web browsing is in the 40's. The other temps were fine though :rolleyes:
  12. Hughm thread starter macrumors member

    Dec 12, 2009
    Thanks to all who took the time to . . . um . . . vent on the subject of heating.

    I feel much better, now.

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