11 Replies Latest reply: May 21, 2011 5:24 AM by Aunty June
Matthias Wahl Level 1 Level 1 (100 points)
Hi,

I've just got my new 27'' iMac with i7 CPU / 4GB RAM / 2TB HDD

Now I figured out that the temperature of the 2TB Hitachi HDD is quite high.
At idle it's about 47°C. During a CPU stress test it climbing up to 59°C !
The ambient is at 16°C.

The default fan speeds (temps) are:
1.000 RPM OPD (36°C)
1.100 RPM HDD (47°C)
938 RPM CPU (40°C)

Under the stress test they are:
1.000 RPM OPD (44°C)
1.550 RPM HDD (59°C)
1.860 RPM CPU (63°C)

I've tried to use SMCfanControl and speed up all fans by +250 RPM. The CPU and the optical drive temps reduced about 2° - 3°C while the HDD temps stays that high. I than turned the HDD fan up to 2.000 RPM which didn't change anything.

Now, about 30 min after the stress test, all fans drops to normal as well as the temps. Except the HDD... while the fan is back to 1.000 RPM the temp is still at 58°C.

I wonder how long it will take under this conditions to fry it... spring and summer are still yet to come...!

Are there any tips and/or hints around here?

Thank you in advance.

Matthias

MacPro 8-Core 3Ghz, 30" Cinema Display, Mac OS X (10.6.5), 8GB-RAM, 1,5TB HD, ATI Radeon HD 4870
  • WZZZ Level 6 Level 6 (12,670 points)
    Since you already know about smcFan, the only other thing I would mention is to run a small fan at the back of the computer. The aluminum back of the iMac acts as heat sink, so running a fan there aimed at the upper left corner -- this is the hottest (I assume it's where the drive is located) -- as you are facing the screen, will help to a certain extent to dissipate the heat. It should be aimed from below upwards to avoid blowing dust directly into the bottom intake grille. I use a small 6" (approx. 15 cm) clip-on fan mounted to the wall behind the computer. Wall mounting avoids vibrations on the desk where the Mac sits. But you might find something even a bit bigger for the size of your iMac.
  • Matthias Wahl Level 1 Level 1 (100 points)
    Thank you for your quick answer. Yes, the upper left corner gets real hot. After looking at the teardown pictures of "FixIt" you can see it's the power supply which is located there, while the HDD sits right up the middle of the iMac. I think it's getting pretty hot at that spot because the CPU fan is blowing up into this direction.

    I turned SMCfc now up to +500 each and will monitor the behavior for a while.

    But I guess you're right... I'll have to install some sort of airflow system onto my desktop :-/
  • WZZZ Level 6 Level 6 (12,670 points)
    And that power supply -- those get really hot -- located so close to the HD isn't helping.
  • Matthias Wahl Level 1 Level 1 (100 points)
    I wonder if this is a reason to contact the support... or have I wait until the drive fails...?!

    Just searched up the net about the Hitachi drive and it seems that the use of this drive for an iMac is worst case. All tests mention the extremely high temperatures up to 55°C and recommended an good cooling system, while they call 50°C the "magical line".

    While my measurements are even above 55°C, it seems that the HDD fan Apple is using is quite ineffective... if not to say useless.
  • WZZZ Level 6 Level 6 (12,670 points)
    Probably contact them. But I don't know what they'll do for you. 58-59: I don't like a drive running that hot. Long term that will slow roast it to death. On a hot summer day here, no air conditioning and with the outside temps around 36-37, my drive will hit 52-53 (which I'm still not crazy about.) And no amount of air flow will help very much, since it's only blowing hot air around. Right now, just browsing, it's around 44.)

    In any case, get AppleCare.
  • Matthias Wahl Level 1 Level 1 (100 points)
    Just called the support.

    The guy told me there is nothing to worry about, till the temperature isn't up to 75°C.
    In his words: "I've never heard of an iMac HDD that died due to temperature issues."

    Well... we'll see.

    I will sign up to an Apple Care Protection Plan anyway... just in case.
  • WZZZ Level 6 Level 6 (12,670 points)
    In his words: "I've never heard of an iMac HDD that died due to temperature issues."


    Well, he hasn't heard much then. The problem is long term slow roasting, perhaps over several years, causing premature failure. The idea you have nothing to worry about until it reaches 75C is patently ridiculous.

    You might want to have a look at this article, with comments, on HD Temps.

    http://www.codinghorror.com/blog/2006/12/hard-drive-temperatures-be-afraid.html
  • Matthias Wahl Level 1 Level 1 (100 points)
    WZZZ wrote:
    In his words: "I've never heard of an iMac HDD that died due to temperature issues."


    Well, he hasn't heard much then. The problem is long term slow roasting, perhaps over several years, causing premature failure. The idea you have nothing to worry about until it reaches 75C is patently ridiculous.



    I think what he meant was that THEY (Apple) don't need to worry about, because the drive will survive at least the warranty.

    I'll spend the extra money on Apple Care, keep an eye on the S.M.A.R.T. Monitor and see what happens.

    Thank you for listening.


    BTW: SMARTMonitor shows a max of 61°C so far... unbelievable.
  • WZZZ Level 6 Level 6 (12,670 points)
    Here's to long life for all our drives. The original Maxtor 10GB in my iMac G3 was still going strong when I replaced it with a 128GB in '08. Don't know about today's drives. Also, the G3 certainly wasn't packed as closely as the new iMacs. When I use it, I run a fan over the top to help exhaust the heat. It's the PAV Board for the CRT that tends to die from heat on those. The drive -- it's the only piece of hardware that has a sensor -- runs cooler than on this one.





    Most accurate is Temperature Monitor (free) or Hardware Monitor (full paying version.)

    http://www.bresink.com/osx/TemperatureMonitor.html

    Message was edited by: WZZZ
  • WZZZ Level 6 Level 6 (12,670 points)
    replaced it with a 128GB in '08


    Correction: meant to say a 160. 128 is the most it can use.
  • Aunty June Level 1 Level 1 (105 points)

    I have similar issue with my new 2011 imac and a WD 1tb drive.  While just surfing the web it's sitting at 46c.  I have noticed it get to 56c after heavy use, gaming etc.  The fans will speed up and I also manually set the fans to close to 4000rm but it doesn't seem to do anything although I can hear the fan.  The WD website says the normal operating temp is 0-60c.  I hope mine doesn't die prematurely.  I also hear it's hard to replace the new iMac's harddrive this year too.  Might invest in applecare.