CD Mac Mini random fan-speed bursts

Discussion in 'Mac mini' started by FatSweatyBlldog, Dec 7, 2007.

  1. FatSweatyBlldog macrumors regular

    Aug 16, 2007
    Every so often my Mac Mini 1.83 Core Duo w/Super Drive will experience a random increase in fan speed...the fan speed increases from 1500rpm to over 5000rpm for a couple minutes, and then will slowly return to normal.

    During these fan speed-bursts there is no increase/abnormal temperatures. CPU and Ambient temps could be at 40C. System load is also minimal (95% idle, eg).

    Haven't heard of this as a common problem, but is this fan behavior indicative of any type of problem?

    Thanks for any help!
  2. FatSweatyBlldog thread starter macrumors regular

    Aug 16, 2007
    So, I guess this isn't a common "quirk"?

    I haven't noticed it happening with any particular program, but the load and temps would indicate that the fan running at full throttle would be unecessesary.

    Mostly, just want to be sure this isn't indicative of another problem etc.

    Thanks again for any help!
  3. tharks2003 macrumors newbie

    Jan 13, 2008
    i've experienced these fan bursts on a 1.66 core duo mac mini

    i've experienced these fan bursts on a 1.66 core duo mac mini

    this happened after the followng sequence of events and is probably unrelated. specifically afer changing back to original 1.66 cd

    changed cpu from 1.66 cd to 2 c2d, then to 2.16 c2d then back to original 1.66 cd

    were you able to resolve?
  4. FatSweatyBlldog thread starter macrumors regular

    Aug 16, 2007
    No fanspeed bursts in a while

    I really never was able to resolve/identify the problem, on my end. But, it never seemed to be a huge problem, just a quirky occurrence.

    In my case, I noticed the occasional fanspeed burst two months after first getting the mini, and over a month after I upgraded the RAM to 2GB. I don't think the upgrade has/had anything to do with the fan speed bursts.

    After starting this thread, I haven't had any more fan speed burts occurrences (that I've seen). Go figure...

    As noted in this and another thread, fanspeed bursts MIGHT be related to an over-worked/over-heated GPU for whatever reason (some thread mentioned JAVA causing this).

    Try and note exactly what you're doing, what applications are open, just before/as the fan speed bursts occur. How often are yours occurring?
  5. GraXXoR macrumors newbie

    Jan 21, 2008
    Also get hair drying speed bursts, but not random.

    Hi, first, let me specify the machine and environment.

    Leopard 10.5 server
    Mac Mini 1.83Ghz C2D model
    Upgraded to 3Gb RAM.

    Temperature Monitor 4.2

    I'm using the machine in a cool room (about 15 degrees right now).
    Idle temperature is:
    HDD 35
    AMB 36
    CPUA HS 35
    CPU C1 38
    CPU C2 40
    CPUA TD 40
    NB P1 40
    NB P2 40

    Fan Speed ~1500 (minimum allowed).

    This is perfectly reasonable at idling, I believe.

    With CPU duty cycle of about 10% generated by server tasks (including short peak demands), the fan tends to increase to about 2500 for short periods and is not really a problem.

    However, I've located specific stimuli which trigger the ridiculously increased fan activity.

    It does not appear to be directly CPU related, but rather certain GPU related activities which cause the problem.

    For example, I open any *long* page in Safari, scroll to the bottom and back to the top using the right hand handle. I do this ten times and my fan is running at over 4000 rpm!

    Artificially scrolling is one thing, but even when I use the scroll ball of an Apple mouse to scroll slowly through a page and the fan rams up to hairdrier mode.

    This is the most annoying thing, rendering it almost unusable for me since I really like to use this for surfing and the noise is up and down like a yoyo every time I scroll 8one tends to do that a lot when surfing).

    As soon as I stop, it starts returning to normal at about 100 rpm per second, so after about 30 seconds it's back down to around 2000.

    Spectrum screen saver for example pushes the fan imediately to 5500 in 15 seconds, but all temperatures is quite stable.

    Yet no temperatures ever went above 50!

    In fact, stop the activity and the continued fan activity pushed my whole computer down to about 10 degrees below idling temp!!!!

    I'm now running Rember with the screensaver on, both cores are pegged at 100%
    my HDD is going down from 40 to about 25 degrees!
    CPU A Heatsink is at 34, CPU cores are at 47 and 49 and appear stable!!! NB1 and 2 are at 40 and 39.

    My fan is now running at 4200 and is quite annoying.

    Now, I cut out the screen saver, reducing CPU usage to one thread yet the fan has not slowed. (CPU coores temp dropped about 45 and 48 degrees - CPU HS NB1 and NB2 are now at 34/35 and 36 respectively).

    At first, I assumed it was my RAM swap, having forgotten the little HDD sensor, but the fan is not pegged all of the time so I don't think it's that.

    It suffices to say that this is not an overheating problem...

    I think, first, I'll check for any small sensors unplugged by the swap.
    Then I should replace the RAM with original 512x2
    If this does not work, I'll backup 10.5 Server and put 10.5 Client back on and see what happens.

    Any ideas?

  6. FatSweatyBlldog thread starter macrumors regular

    Aug 16, 2007
    Here's a quick suggestion: have you tried another browser, like Firefox?
    Try doing the same scrolling thing in Firefox and see if you get the same results.

    Good luck though. Let us know how it goes and what you find.
  7. happygaijin macrumors newbie

    Jan 23, 2008
    Similar fan speed problems


    I have similar problems.
    When using the mac mini together with an Elgato 610 digitalTV decoder and watching any program in full screen mode for more than ten minutes the fan goes up to over 4000 rpm! Same as you, all the temperatures are fairly low, the highest one reaching a staggering 54 degrees C. And the CPU idle time is between 85%-90%, so the Mini isn't working that hard.

    I'll continue my research and follow yours with interest!
  8. three macrumors 65816


    Jan 22, 2008
    Washington State
    I'll try in my 1.66 CD mini. See if my fan does the same thing.
  9. palm disaster macrumors newbie

    Jan 18, 2006
    I've got a new 2.0 Ghz Mac Mini w/ 2 Gb RAM, and I noticed that the fan really speeds up whenever a screensaver runs. Otherwise, it's fairly quiet.

    So I installed smcFanControl which is a great free program that has allowed me to do some precise checking.

    Usually the mini processor runs at about 50° C with the fan at 1500-2000 RPM. When the screen saver starts up, the fan first runs up to 4700 RPM and stays there for about 10-15 minutes. Then the fan starts slowing down, and after about a half hour of the screen saver running, the fan was down to 2700 RPM which is about 700-1200 RPM faster than usual, and the TEMP OF THE PROCESSOR WAS DOWN TO 47° C. After turning the screen saver off, the fan slowed down to 1500 and the temp went up to 50°C, which seems to be the normal operating temperature of the processor.

    This seems to confirm what common sense would dictate--the fan doesn't need to speed up to run a simple screen saver.

    Therefore, this seems to be a small area where Mac OS X could be improved.

    Here's a link to a discussion of the topic at the apple support discussion forums:
  10. GraXXoR macrumors newbie

    Jan 21, 2008
    The Wrath of Fan. Is 10.5.2 / GU 1.0 a possible fix?

    I just installed 10.5.2 and Graphics Update 1.0 and today I noticed that I can browse Safari for longer before the fan speeds up.
    Before, within a couple of longish pages (like this one) scrolled down to the bottom, the fan would kick in and be up to over 4000 on my stock Mac Mini C2D 1.8 cooling the CPU nicely down to about 40 degrees in the process.

    Today, I noticed with casual browsing that the fan rarely reached above 3000.

    I'm not sure if this is subjective or not, but it would seem that to some extent, Safari no longer causes the fan to spin up quite as quickly as it did before.

    I'm currently running over VNC, so I can't judge entirely, but if I'm mistaken, I'll write back.



    Oh well, it seems I was mistaken. By resizing the Safari window around and rapid scrolling, I managed to max out the fan at 5500 within 30 seconds, cooling my CPU down to a new record of 35C! Wait, make that 33... nope... 31...
    After the pressure's off the processor, the fan speed continues to cool the whole caboodle down further and further.

    Still, it seems that I can browse a few more pages than before without incurring the Wrath of Fan.

    Current Temperature, 29C !! (the room abient is about 14C).
  11. wendpick macrumors newbie

    Sep 28, 2009
    Loud, excessive rpm fan

    I have been battling with fan speed on my iMac recently as well.
    I installed iStat which shows normal temps, but the fan at 4000rpm - for seemingly no reason at all.
    I have spent hours with tech support, who then upgraded me to a higher level of tech support. But still the problem continues.

    I would like to ask this forum (the Noisy Fan Club folk) 2 things.

    1- Have you recently upgraded from Leopard to Snow Leopard. Did the problem only start then?
    2 - Have you tried booting up into Safe Mode and seeing if the fan speeds up while you work in Safe Mode?

    My fan only started this behavior after upgrading to SL, and I am now running in Safe Mode with my fan totally,blessedly silent at 1198 rpm

Share This Page