MacBook Pro slow to increase fan speed

Discussion in 'MacBook Pro' started by pbrstreetgang, Jan 14, 2010.

  1. pbrstreetgang macrumors newbie

    Jun 26, 2008
    Hi, I have a base model June 09 13" Macbook Pro running 10.6.2, during normal use CPU temp. is fine, lower than my previous Macbook 07 edition. However, when I use handbrake, the temp spikes very quickly, I know this is normal as the processsors are being used at 100%. However, unlike my old Macbook, the fan takes a long time to spin up to counter the increase in CPU temp. I see 101 degrees centigrade and the fans are still at 2000rpm. After a few minutes they react and slowly increase to maximum. I am not comfortable with this temp, my old Macbok used to only get to 85 degrees centigrade. I have read about SMC fan control, is there a way to set this so that it increases the fan speed at lower temps without having a detrimental effect on battery life. Thank you in advance,
  2. iLog.Genius macrumors 601


    Feb 24, 2009
    Toronto, Ontario
    I don't think the speed at which the fans spin at really has an affect on battery life. I'm not saying it doesn't affect battery at all, it isn't significant relative to what you're doing to make the fans spin that fast which probably hitting the battery more. You say you're using Handbreak. Using 100% of the CPU is going drain the battery and the fans spinning 3000RPM plus isn't really going to speed up draining the battery.

    I use Fan Control and set the lower threshold to 60 C and higher threshold to 80 C and leave the fans at their default settings of 2000RPM.
  3. Matthew Yohe macrumors 68020

    Oct 12, 2006
    I'm betting you don't have a background in electrical engineering?

    If I'm right, then why are you concerned? What makes you uncomfortable with this temperature? Because your previous MacBook which was made years ago with different parts, and technologies would turn on its fan sooner than your current MacBook Pro?

    There is no need to manually control your fan speed. There is no need to over think your Mac experience. Just use the machine as it was intended. You are far below even the critical catastrophic temperature of 125 C.

    If there are any problems with MacBook Pros failing early because of incorrectly handling CPU fan speeds, there will be broad and wide-ranging reports of such an issue, and Apple will be forced to make good.
  4. battery1999 macrumors newbie

    Jan 14, 2010
    Is it a good news?
    Sound like a good idea, but I think MacBook's temperature maybe increase!:rolleyes:
  5. gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N

    And, I might add: one reason it sits at a "high" temp before ramping up the fan(s) is to give the heatsink a chance to absorb some of the heat. Since you're looking at the internal die temp, you don't have a good idea what the cooling system is doing - which is made up of the heatsink PLUS fan(s). The heatsink can do its job without the fan, to some extent. If Apple chose to have the fan(s) running prematurely or at higher average speeds, then you'd end up with something resembling most (if not all) PC notebooks out there [I've seen] - i.e. noisy!

    Don't worry about it - the MBP will take care of itself. My 17" ubMBP runs noticeably cooler than my 2.33GHz 17" C2D did. The only things you should do is keep the rear air vents clear of obstructions and try and have the machine resting on a firm surface (which helps air circulate around the case).

    From the 17" ubMBP Early 2009 users guide:
    Proper handling Set up your MacBook Pro on a stable work surface that allows for adequate air circulation under and around the computer. Do not operate your MacBook Pro on a pillow or other soft material, as the material can block the airflow vents. Never place anything over the keyboard when operating your MacBook Pro. Never push objects into the ventilation openings.
    The bottom of your MacBook Pro may become very warm during normal use. If your MacBook Pro is on your lap and gets uncomfortably warm, remove it from your lap and place it on a stable work surface.​
  6. pbrstreetgang thread starter macrumors newbie

    Jun 26, 2008

    Many thanks to all for the replies. Gave me good piece of mind, Thanks

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