CPU temperature under bootcamp with Windows 7

Discussion in 'Windows, Linux & Others on the Mac' started by jim468, Aug 27, 2011.

  1. jim468 macrumors regular

    Jun 14, 2009
    While watching youtube/flash or installing software (e.g. Adobe Acrobat updates), the CPU temperature on my new MBA 13" (1.7/4/256GB) goes pretty high, but ironically the fan speed does not increase to take care of that.

    Attached is a screenshot I took using speccy, where we see that the CPU temperature is 94 C, but the fan speed is only 2001 RPM.

    However, when I run OS X (Lion), the fan speeds up as necessary to accommodate the increase in CPU temperature.

    Has anyone else experienced something like this? I did not put this under the "Windows on the Mac" section as I was not sure if this is something pertinent to MBA or all Macs.


  2. komoornik macrumors regular

    Jul 29, 2011
  3. minnus macrumors 6502

    Aug 12, 2011
    I am actually currently stress testing the CPU on bootcamp right now. I can tell you that on load, the CPU gets slightly warmer than on the Mac side (95/96 Mac, 97/98 Windows). Not sure if they are just discrepancies though, since both OS much see the same temperature and interpret it differently depending on software used (iStat Pro on Mac, RealTemp on Windows)

    On both Mac/PC, the CPU would seemingly rather get warmer than noisier. It won't kick up to 6k+ fan speeds till is very hot.
  4. iphonsteve4ajob macrumors regular

    Aug 6, 2011
    That is a bit odd. I do not use bootcamp, but an Air running at 95C (cpu shut down temp is 100C) with fans at 2K rpms (idle temp) cannot be normal. I'm assuming this program was running for at least a few minutes? You should start to see fan speed increase as you pass 70-75C.

    Perhaps the system monitor was not working properly?
  5. jim468 thread starter macrumors regular

    Jun 14, 2009
    I don't have HWMonitor. I will try it and update here later. However, I am not sure if that's the case.

    Thank you for this info.

    You are right. On OS X, I see the fan speed and noise both increase as the CPU temperature crosses 70-75 C. However, on Windows (Bootcamp) I did not notice the same.

    Usually in MBA, the fan noise increases a lot as its RPM increases (2K vs. 6K RPM). However, in this case I could barely hear the fan and that's why I think maybe the fan was actually running at 2K RPM.
  6. Quad5Ny macrumors 6502a


    Sep 13, 2009
    New York, USA
    Jim468 95c seems extremely hot. The max temperature for the i5-2557M is listed as 100c.

    I don't think it should run anywhere near that temperature. It's possible Apple screwed up applying the thermal compound or that the fan controller is not working right (or maybe even the heat pipe could be damaged).

    Try resetting the SMC; http://support.apple.com/kb/ht3964. Other than that, I don't have any solutions. Sorry.
  7. falconxp macrumors newbie

    Jun 5, 2011
    The Netherlands
    I get the same high temps with my Air 11 i7.

    I disabled the cpu turbo mode in Windows 7 which keeps my Air 11 i7 relatively cool in Windows 7.

    Control panel -> Power Options -> change active plan settings -> change advanced power settings -> processor power management -> maximum processor state -> On battery / plugged in : 100% -> 99%
  8. Bob Coxner macrumors 6502a

    Mar 24, 2011
  9. falconxp macrumors newbie

    Jun 5, 2011
    The Netherlands
    If the controller is supported in speedfan is should work. Bootcamp installed OS have direct access to the hardware unlike under vmware or parallels installed OS.
  10. jim468 thread starter macrumors regular

    Jun 14, 2009
    Thank you for the link to resetting the SMC. I tried that, but did not notice any change. The surprising thing is that the CPU temperature and fan speed behave as it should when I am running Lion. This discrepancy is only observed in Windows 7 via bootcamp. Moreover in Windows 7, I also noticed that if the CPU is at 95+ C for a few minutes, then, the fan RPM slowly starts to increase (e.g. 2000, 2030, 2060, 2090, etc...) and after a few minutes it reaches till 4K+ and eventually brings the temperature down to approximately 80 C.

    On the Lion side, the fan RPM reaches 4K+ as soon as the CPU hits 80+ C.

    I think this is due to the bootcamp drivers, but that's just my guess.

    Thank you for this information. I tried that and I was successfully able to disable the turbo mode. However, the system feels a little slow after I made that change. Also youtube (which I use a lot) became jerky at higher resolutions.

    One of my reasons for buying the MBA (mid 2011 model) was the new turbo mode introduced in i5/i7 and hence I am a bit hesitant in disabling that. Having said that, I did notice a reduction in temperature by disabling the turbo mode, but I don't plan on keeping it that way, as youtube gets jerky : /

    Thank you once again for the tip.
  11. falconxp macrumors newbie

    Jun 5, 2011
    The Netherlands
    Don't play alot of youtube videos on my Air 11 but they do run ok on my machine. Use it mainly for browsing, MS office and video files (avi,mkv) with gomplayer. Windows is non turbo and Mac OS is turbo enabled.

    What browser are you using for you tube and did you try another one? Firefox, IE, Chrome or Opera?
  12. jim468 thread starter macrumors regular

    Jun 14, 2009
    I mainly use Chrome and Firefox sometimes. I recently noticed that one of the reasons why youtube may get jerky at higher resolutions can be because I have an external display (1080p) connected to my MBA which I use as my primary display. I usually watch youtube on this external display and that's when they get jerky.

    If I disable the MBA's display and only use the external one, then the videos get a little better.

    However, in both cases (with or without MBA's internal display in use) the video gets a bit jerky if I disable the turbo mode.

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