I7 iMac - Random CPU fan surges

It's happened three times this month, 2 of them today - my CPU fans will suddenly rev up to 4,000 RPM, and iStatPro will show the CPU temperature as "--". The first time it happened, I was worried that the machine got too hot. The second time, I had just sat down at the computer in the morning... the top of it was hardly even warm.
Both times, after shutting down and rebooting the fans went back to normal, but the computer performed poorly in graphical tasks (gaming) until I did an SMC reset, which brought it back to normal.
Two of the times it happened, I was playing Modern Warfare. The third time, I was watching a Friends DVD. All 3 times, system was 90-99% idle and all other temperatures were moderate. The fact that on one occasion it happened when my computer was still cold from being asleep all night makes me think that it's a false sensor reading that makes the computer think it needs to crank that CPU fan.
I haven't done the recent SMC update, since I never plan on using this computer as a display for another machine... should I install it anyway?
Thanks.
-Nick

4000 rpm is a lot thats not normal, are you doing some heavy processing like rendering video or encoding video, its the only way your cpu start to ask for the sensor to fire up the fan so it could cool down the system. That is normal if your rendering video.
In my case its weird also I am using Ableton live suite 8 to produce music and when I am looping some sound to compose it with some others to match up in sync it uses the cpu but only 10 percent maybe. Here is the thing my computer start to rev up once in a while, when I a doing this, I do notice that maybe its spring and the room temp is higher and there is a chance that the computer would start to heat up. I mean I got this computer in Feb 2 and of coarse it wasn't having this problem but as we head towards summer it is heating up once in a while and the computer fans do fire up.
I am guessing the i7 do have a tic to get hot and once in a while the fans fire up, but its not normal that it does it frequently just idle, it should fire up when the processor is being loaded with processing power, for music production synthesizer running midi notes, video rendering which is a big load for the CPU, etc.

Similar Messages

  • Why is my iMac's CPU fan making a lot of noise?

    Hello!
    My 27" iMac (late 2009) is making a lot of noise for the last few months. The noise doesnt occur when you start up, but after you do something what is not really intensive for the computer suddenly the CPU fan is going up to about 4000 rpm. I have tried resseting the PRAM and the SMC but it won't help. I have inserted an image so you can take a look for yourself!
    Kind regards,
    Emiel

    Try resetting the iMac SMC and PRAM reset again, this time do each reset 2x. On occasion the first time does not work, but if it continues to be noisy then you probably have a mechanical problem and the fan may need replacing.

  • Imac randomly freezes   fan runs loud

    Hello,
    My imac g5 randomly freezes. When it does freeze the fan kicks in and is very loud. This is a stock g5 Imac with no new software loaded. The only applications run on this machine so far are safari, and Mail. Does anyone have a clue as to what could be wrong? I've had the machine for 2 months and it has run fine untill the last week of random freezes. Also does anyone know apples policy regarding replacement or repair? I do have applecare. any advice would be appreciated, thanks,
    Dan

    Hi,
    I have exactly the same problem. I've had it for a couple of months now. My iMac G5 (iSight) is only a couple of months old - I got one of the last ones just after the intel came out. The freeze occured loads with 10.4.6. I've just had it again with 10.4.7 - my first time since I updated with the full combined installer a few days back.
    I regularly repair permissions. I have run fsck from single user mode. I have run apple hardware test - no faults. I have checked/repaired the disk from the install disk - no faults. I have removed all external devices - I previously suspected it might be a USB hub causing the problem but no. I have not removed additional ram as yet - that is my next step though it pains me to be doing such things when I bought the computer from Apple and you would think they would have installed Apple approved/top quality ram.
    It is very weird behaviour. Never experienced it in all my mac owning days - and I've got/had a few. I had hoped it was a combination of 10.4.6 and the iMac G5 (iSight)... but the latest update has not fixed the problem. And I find it hard to believe it may be the RAM. Because surely RAM just doesn't fail that often?!? And like this?
    Any suggestions would be much appreciated.
    iMac G5 2.1   Mac OS X (10.4.7)   1.5 GB Ram
    iMac G5 2.1   Mac OS X (10.4.7)   1.5 GB Ram
    iMac G5 2.1   Mac OS X (10.4.7)   1.5 GB Ram

  • IMac randomly shutting fan off?

    Good Day!
    About every 20 or 30 minutes, even while I'm just walking by my mac, I hear a click, and it appears, or sounds like a fan is shutting off. Also on occasion, right when i click on an application to open it, I will hear an internal click and what sounds like the winding down of a fan, I then get the "thinking" cursor, (don't know what that's actually called) for about 10 seconds, then the application I clicked on opens. Weird!! Any thoughts?
    Thanks!

    Open System Preferences -> Energy Saver. Look at the check box in the lower left of the window. It says "Put the hard disk(s) to sleep when possible" If that box is checked then uncheck it. Sounds like your hard drive is asleep when you hear this noise. It would also explain why your application delays opening. It's waiting for the hard drive to spin up.
    Just a possibility.

  • 24" iMac summer 2008. CPU fan runs at highest speed, some times goes to "sleep" mode. t' is about 35'- 42'C. Run hardware test: 4sns/1/40000000:tlop-130.000, next time 4sns/1/40000000:tlop-128.000 errors. Reinstalled all softwere. Nothing changed.

    24" iMac summer 2008. CPU fan runs at highest speed, some times goes to "sleep" mode. CPU t' is about 35'- 42'C. Run hardware test: 4sns/1/40000000:tlop-130.000, next time 4sns/1/40000000:tlop-128.000 errors. Tried SMC, NVRAM, PRAM. Reinstalled all softwere. Nothing changed.

    I suspect you have hardware problem with a fan sensor. Doing a software install will not help the machine needs to be taken in for service. If you run Apple Hardware Test in Extended Mode it should reveal the error code. If it does not then run AHT an additional 2-3 times to be sure in Extended Mode. Each pass will take about 30-60 minutes.

  • IMac cpu fan running at full rpm

    hi all
    A few days ago my cpu fan started running flat out. I have done the smc or whatever it is caled reset thing where you unplug the cored ect.
    I have done the hardware test with no bad results.
    I have checked activity monitor for cpu usage and there is nothing unusual there, so I can only guess that the cpu temp censor is faulty.
    I should also add that this machine has been running non stop since mid 2007 , with the exception of the odd blackout and restart, thats pretty amazing i think.
    maybe its time has finally come ;(
    any clues ??
    thanks

    SMC is firmware and OS X is software, which has nothing to do. Furthermore, you are using a very old iMac, so SMC should not have been updated with OS X 10.10.2.
    If you have tried a SMC reset and it did not work, run Apple Hardware Test (make sure you choose an extended test) to see if there is any problem with a temperature sensor or anything like this -> Using Apple Hardware Test - Apple Support
    Note that you may need the DVDs that came with your Mac in order to run it. If you get an error at the end of the test, please copy it here.

  • IMac i7 - Strange CPU-fan problem!

    Hi,
    my name is Chris and I'm living in Germany. Sorry for my pigeon english, I'm not very good in languages... Nevertheless I will try to describe my problem.
    I have received my iMac last saturday. It's an i7 with 2TB hard drive. On sunday suddenly the CPU-fan went nuts, spinning with about 3500 rpm. At that time there was no heavy CPU load at all.
    Neither P-RAM- nor SMC-resets fixed the problem, the CPU-fan was running at full speed all the time. On monday morning (the i7 was switched during the night), the problem was still persisting. Hence, I contacted Apple and they promised to send me a replacement for the i7 in about three weeks.
    Later on this monday, I received a package with additional 4GB of memory I had ordered for the iMac. Although the iMac was making noise comparable to a 747, I decided to build in the additional 4GB of RAM, just to play a bit around with an "8GB machine". The assembly of the additional memory was pretty easy, basically everything was working fine (memory wise). But the CPU-fan was still continuously at around 3500 rpm.
    Afterwards, I decided to clean up the computer a bit by using the "automatic" script within "Onyx". I started the procedure and left the room.
    When I came back about 1 hour later, there was total silence in the room. In first instance I wasn't surprised very much, because the iMac was obviously in the sleep mode. But I was really surprised when I woke it up again: The CPU- fan was back to normal, spinning with 940rpm. Almost completely silent.
    Any ideas what happened? Can there be a connection between the "fan-went-nuts-issue" and the Onyx scripts?
    What shall I do? My iMac is behaving now, but I have already ordered replacement...
    Best wishes,
    Chris

    Yes, I have seen this thread, thank you.
    When the CPU-fan started to spin at 3800, one of the first thing I tried was putting the iMac into the sleep mode. After I had done so, I woke it up back again almost immediately (about 1 minute later) by pressing the space bar. But for some reason, the iMac woke (with normal fan noise) and then immediately fall back into sleep (after being about 10 seconds awake). A "proper wake up" was not possible, since it was sort of an infinitely loop of waking up and falling asleep. A reboot via the power button was necessary, whereby the fan went back to 3800 rpm.
    And then I performed this Onyx-run (as mentioned in my first post), and afterwards the iMac went to sleep mode automatically. It stayed in the sleep mode for about an hour or so, and after my next wake up call it was cured.
    Really strange. Either it was cured by the maintenance-things Onyx did to the cache/system files, or by being in the sleep mode for about one hour. I also can't exclude influence of our Lord, since I was behaving in the last year...
    Somehow I have lost my trust in that machine. Even after the fan went back to normal behavior I am still not sure if I should cancel the replacement order... I am open for recommendations from your side.
    Best wishes,
    Chris

  • IMac CPU fan on full speed from start up

    Hi,
    For about 3 months now I've had a problem with my iMac where the CPU fan runs at full speed from start up, until I turn it off. It is extremley noisy and frustating.
    I am pulling my hair out trying to fix it.
    So far I have reset the SMC and PRAM and downloaded fan controllers. I've also opened it up and checked the sensors and cleaned out all of the dust, but this annoying problem still persists.
    Is there anything else I could try that could fix this problem?
    Thank you very much.

    Thank you
    I have tried to run the AHT many times, but for some reason I can't get it to work. I even tried booting it from the insitallation disk which someone else suggested.
    I'm not sure where to go from here

  • IMac CPU fan speed

    I recently just had Apple look at my iMac, reason being for the glass to get cleaned on the inside as well as the LCD to get replaced. Waited a week, went and picked it up, only to be disappointed by the fact that the LCD wasn't replaced.
    Called Apple, they sent a certified technician to come install my LCD panel. Where he came from, was farther than the closest Apple store near me. Anyway, he came and replaced my LCD, and we tested it to make sure everything was good. It was, and I asked him to leave the glass on, since I was going to be cleaning the insides out. Apparently 3 years of dust accumulation looks pretty gross on the inside .
    I ended up taking the motherboard out, to clean the heatsinks and to reapply thermal paste on both the GPU and CPU. They did have an excess amount on, but for the most part was done A LOT better than my early 11 17" 2.3 i7. I ended up taking the hard drive out and swapping it for a 80gb Intel x-25m and tagging the temp sensor on it.
    After putting it all together, I noticed that the CPU fan runs around 3700 rpm. I tried resetting the SMC, no luck. I can use fan control or SMC and turn the CPU fan up, but it won't go below the 3700 mark.
    One thing to note, is that I have NOT put the glass back on, as I do not have any suction cups. I do know that I plugged everything in correctly, as well as taking the HDD temp sensor from the 1tb stock HD to put on the SSD I installed.
    So what could this be?
    ps. The Apple certified technician at the Apple store straight up told me that the iMacs DO NOT use thermal grease (I asked him if he could reapply some). HAHAHAHAHA what a dummie.

    What kind of thermalpaste did you use? some types of processing units need special kinds of paste.
    Are you shure that you have fitted the cooling system on the processing units thight enough?

  • CPU Fan going crazy (over 3500 rpm) all the time iMac 24"

    Hello,
    I have had an iMac 24" since Aug 2009. I had no problem until up a month ago (coincidentally after I installed Mountain Lion).
    The CPU fan becomes very noisy, reaching 3500 rpm and more. I checked and the CPU temperature is around 90C when this happens.
    It happens invariably after very little usage of the computer. Sometimes it's when I'm watching a DVD, sometimes is when I'm copying files from a USB hard drive, sometimes I'm just surfing the web.
    I have brought my computer to the Apple Store twice already. The first time they told me I should reinstall the OS from scratch, after erasing the disk (which I did), the second time they told me they had found the problem and fixed it, for free! but it presented itself as soon as I turned it on back home.
    The CPU temperature is around 80C right now, and I only have safari opened and I haven't reinstalled any program since I reinstalled the OS.
    Do you have any idea of what it could be? Could it be that the sensor is detecting a wrong temperature? In this case, could I set the fan speed manually? I know it is not advisable, but the people from the apple store are not helping
    Thanks for any help you could give me,
    Biagio

    Please start by doing a SMC Reset,
    Shut down the computer. 
    Unplug the computer's power cord and all peripherals.
    Wait fifteen seconds. 
    Attach the computer's power cord. 
    Wait five seconds, then press the power button to turn on the computer.
    If necessary repeat process.

  • IMac CPU fan speed at full blast.

    I have a 20" iMac (A1224) and when you srtat it, the CPU fan goes full blast and never stops.
    SMCFanControl reports the CPU fan at 3900 RPMs (full blast) but what is it trying to cool?  The temperature is 27 degrees celsius (80° F), Activity Monitor says 93% of my CPU is idle. I've done all the normal SMC/PRAM stuff and it seems that my CPU temps is just fine. Something needs to be replaced.
    Sensor
    Fan
    DC Power Supply/SATA/Inverter cable
    Also, yesterday it repeatedly shut down and restarted itself over and over and over until I unplugged it.

    I realize that Eric. However, I am currently unable to: https://discussions.apple.com/message/21827955#21827955

  • The iMac CPU fan going ape **** after upgrade

    Just installed Mountain Lion - result: CPU fan is at 3000 RPM constantly. CPU temperature 50 celcuis, GPU around 70. Nothing serious is running - just Safari iTunes and Mail.
    Any suggesions?

    If you're running ESET Cybersecurity you may need to upgrade.  Older versions have been causing a crash in the Launch files which means reportcrash constantly triggers (drains battery and kicks in the fans).
    Here's the fix...
    First, check you've got a problem with crashreport (run Activity Monitor and select 'All processes').  If crashreport is at the top of the list with 100+ % CPU time and you have ESET then it's possibly this issue.
    Go to Eset website and download the latest version of Cybersecurity and run the dmg file once downloaded.  Click the 'uninstall' button to remove and you should (hopefully, as I did) see the crashreport stop.  You can then reinstall ESET (I have done with the newer version with no problem).
    I'm not sure if a straight install over the top (upgrade) will work - easy to uninstall and reinstall in a few mins anyway.
    I hope this helps a lot of people out!

  • DualCore Center CPU Fan at 0 rpm randomly ?

    Hello everyone.
    I recently got a new system with an MSI P965 Platinum motherboard, it's the first time I use MSI, before this I only had Soyo, Asus or Gigabyte motherboards.
    System specs:
    -MSI P965 Platinum
    -Core 2 Duo E6400 @ 2.13 Ghz (stock speed, nothing overclocked)
    -(2x) 1Gb OCZ 667 Mhz DDR2 RAM
    -Sapphire ATI Radeon X1950XT 256MB GDDR3 PCI-E
    -500W Powercooler PSU (+3.3v_28a,+5v_34a,+12v1_20a,+12v2_17a)
    -Western Digital SATA Hard Drives WD3200KS, WD2500KS & WD2000JD
    -Pioneer DVR-109 & DVD-120
    -WinXP Pro SP2
    My problem is that DualCore Center ocassionally pops and triggers an alarm indicating that the CPU fan speed is 0 rpm, it takes a couple of seconds and goes back to ~1950rpm and then again to 0rpm. At first this happened a couple of times while playing heavy 3D games, but I thought it might have been something related to the games so I just close DualCore Center before playing. I assume this because I've seen this kind of behavior on Asus PC Probe software in the past.
    However I just saw it pop while browsing the internet and it kept going up and down so I had to close it or mute the sound.
    I can see the cpu fan since the case is open and it looks ok, although I was thinking if the fan is indeed loosing power in 2 second intervals, I may not be able to notice it with my eyes.
    CPU temp is around 32~34 C, System temp is along those lines as well. I think when CPU load is 100% the worst temp that I've gotten was maybe 40~42 C, but I don't think it ever got above those values.
    I believe DualCore center version is 2.0, I had to download it from the MSI web site because the version that came with the motherboard Driver CD did not work.
    Any ideas, thoughts or comments will be highly appreciated.
    Thank you.

    Don't use Dual Core Center and you will not have this kind of problem.
    Whenever I use Dual Core center, alarms go off, stuff starts blinking, the system restarts or it freezes, hangs, causes strange error messages or suddenly decides that my system doesn't meet the requirements to run it at all.  On very beautiful and sunny days only it seems to work fine....
    As long as I stay away from that strange tool everything is fine and stable.
    Dual Core Center ist not the best tool ever written and considering the fact that it causes problems on many systems, the best idea is usually to delete it and never touch it again.
    What do you need it for anyway?

  • IMac randomly shuts down

    My IMac randomly shuts down. I have the energy saver set for computer to sleep after 1 hour. I have not installed any new software. This problem began about a month ago. I have to use the restart button and always get an error, that the computer shut down unexpectedly. I copied one of the Panic Reports if that will help resolve the problem. I have checked the "maximum temperature" in Console and get no messages and many messagfor "shutdown".
    Istat:(Celsius)Temps
    HD:MacIntosh 49
    CPU 39
    CPU Heatsink 39
    Fans:
    Optical Drive 798rpm
    Hard Drive 1599rpm
    CPU Drive 1199 rpm
    I also use Airport Extreme Version 7.4.2
    Any ideas?
    Thanks
    Message was edited by: Raydream

    Hi Raydream ,
    Try another outlet in another part of the house
    Do you use a surge protector? do you have another surge protector to try? Just in case some thing is wrong with the surge protector your using. Also dose any thing else turn off or just the computer.
    things you can try:
    Make sure your software is up to date:
    http://support.apple.com/kb/ht1338
    Verify your firmware is up to date:
    http://support.apple.com/kb/ht1237
    reset the SMC:
    http://support.apple.com/kb/ht3964
    reset NVRAM:
    http://support.apple.com/kb/ht1379
    if your still having the issues I would back every thing up and then book an appointment for the closest apple store genius bar.
    http://www.apple.com/retail/geniusbar/
    if there is no apple store near you i'd locate an authorized repair center:
    http://support.apple.com/kb/ht1434 , for the US it's http://www.apple.com/buy/locator/service/
    you can also call apple care (1 800 APL CARE)

  • IMac Randomly Shuts Down -Overheating Problem?

    I've posted in these forums once before about my iMac randomly shutting down. I believed I had solved the problem by following another users instructions which were as follows:
    "Machines that are just randomly shutting down are usually caused by defective hardware. The only thing that can be done about that is to call Apple and have it replaced or serviced. There is probably not any one particular solution as it could be any number of the internal components failing and the resulting symptoms could be the same.
    If you'd like to do some hardware tests yourself before calling Apple that can be done. First try resetting the SMC: http://docs.info.apple.com/article.html?artnum=303446
    Next insert the original gray install disk, restart your iMac, then hold down the "d" key until it boots up into the Apple Hardware Test. Run the extended test.
    Also if you have Apple Care install TechTool Deluxe from the cd provided. Then run TechTool on your system."
    I also removed and replaced of a defective external HD that I thought my be causing problems. But after all these steps, the machine kept turning itself off.
    I had read in some forums that it was due to the internal temperature of the iMac. So I downloaded smcfancontrol 2.1 and increased the fan speed on the internal fans. This did bring down the temperature as revealed by the iStat Pro widget. However, I still had another shutdown.
    So I turned off the machine, went to bed, and this morning when I turned it on iStat Pro said these were the internal temperatures of the iMac:
    CPU A 77 degrees F
    GPU 85
    GPU Diode 88
    GPU Heatsink 85
    Ambient 61
    Memory Cont. 74
    Airport Card 112
    HD Bay 1 76
    I find these numbers to be unbelievable. Especially the airport card. When the whole system seemed to be running hot, the Airport Card said it was 122. It always says something above 100 degrees. The other temperatures also seem out of whack. How can the CPU be 77 degrees after 10 hours of being completely powered down in an office environment that is only 55 degrees?
    Has anyone else run into a similar problem?
    Has anyone else found the problem to be a faulty temperature sensor (and is there a way to reset it, or does it have to be replaced)?
    Overheated? in Oregon...
    Message was edited by: OregonMac7

    Certainly sounds like a case of the left hand not knowing from the right, huh
    Well, I have my call in, and I am getting onsite service to replace the logic board, as per Apple's recommendation.
    I'm reading the other longer thread (171 replies), and it's disheartening to hear how some of the "geniuses" are handling this problem. They can't replicate it by leaving the mac running overnight, so "the problem doesn't exist". Hello! It's *random*! As in, not easy to replicate!
    I'm also a bit disillusioned that the popular Mac sites (TUAW, etc) haven't picked up on this story yet. I emailed TUAW the link to the long thread, and they ignore it. Usually when this gets more "mainstream" press, then Apple finally steps up, acknowledges a problem, and serious fixes are made. Right now, it's a bunch of complainers (me included) in some threads on the Apple site.
    I took a huge leap last November, and went from PCs to the Mac platform, after working on my personal migration plans for a month prior - how to move from my photo editing on the PC to the Mac (I wasn't about to buy another full copy of Photoshop, for eg, but I did find out I could upgrade from Win PS to Mac PS), if all the programs I use for photography and design were available on the Mac, learning the ins and outs of shortcut keys, how things are done, etc etc, and was so happy initially when I got the Mac and said goodbye to the PC.
    Now I'm literally afraid to do any serious work on the Mac for fear of the "pulled plug" syndrome losing the last 20, 30 minutes of work I've been doing because I didn't save every 2 minutes. And iLife's Pages doesn't autosave (much to my chagrin), so I've lost some long correspondence and articles typed because I didn't save it before the pulled plug o' death.
    Not a very nice computing experience.
    As a suggestion, maybe everyone reading this and the other thread can flood TUAW.com with a news suggestion to cover this problem. Engadget, Gizmodo too while you're at it. I think once these million-viewers a day blogs cover it, we'll see some real action from Apple.
    Just a thought....
    Mark

Maybe you are looking for