mac pro early 2008 - fan noise on start up & constant "whirring" sound

Discussion in 'Mac Pro' started by Col127, Feb 14, 2008.

  1. Col127 macrumors 6502

    Sep 13, 2003
    hey guys,

    wondering if anyone has any ideas about my mac pro early 2008 (2.8 ghz 8-core). i've got the standard 320 gb of hd space, 2 gb of ram, and the nvidia geforce 8800 gt :) every time i start up the machine (from power off), i hear the fans go on full blast for about 2-3 seconds and then they go quiet. does anyone else have this happen to them?

    also, during normal operation, i hear a constant "whirring" type sound - it fades in and out... is this normal? any ideas what's causing it? it's pretty loud... all i have open right now is safari and this is the sound it makes....

  2. aLoC macrumors 6502a

    Nov 10, 2006
    The 2-3 seconds full blast is normal, because the fans go full blast until the fan control software is loaded (which takes a few seconds). Once everything is booted though it should be very quiet (not silent, but quiet).
  3. deathshrub macrumors 6502

    Oct 30, 2007
    Christmas Island
    For me it doesn't seem like the system fans are revving up, but the graphics card fan is definitely going ape-**it for those first few seconds.

    (BTW, machine arrived today, and I am loving it. :) )
  4. Infrared macrumors 68000


    Mar 28, 2007
    That's normal, I understand.

    I hear something that may be similar. Then again, maybe not.

    From reading around, I'd say the most likely candidate is the disk drive.
    Alternatives: fan or PSU noise.

    It's very hard to say just given your description: maybe you could
    make a sound recording for us?
  5. Sandock macrumors member

    Aug 10, 2006
    Calgary, Canada
    Yep, mine does the same constant whirring type sound that fades in and out. The same thing with the fans going full blast during start up. Probably normal, I suppose; I've read the same from other threads. Fact is, I check this forum all the time just to see if any one has the same case as mine. I don't worry about it, though it can be irritating sometimes.
  6. Rodrigo Lima macrumors newbie

    Feb 16, 2008
    Mac Pro 8 core_4MOT/2/40000004:EXHAUST

    My very new Mac Pro 8 core with 2GB RAM is making, sometimes, a loud and constant fan noise, something like a full power rotation that stay sounding for a long time... At most, it starts when the computer come back from the sleeping mode. But sometimes the noise stops and it works quiet. This is coming and going... I've tried to run the AHT (Apple Hardware Test), to obtain some diagnostic about any problem and I've found an error:

    4MOT/2/40000004: EXHAUST

    Does anybody know what is this and how I can fix that problem???


  7. JonR356 macrumors member

    Jun 8, 2007
    Same whirring noise here. may try reseating the hard drives
  8. netdog macrumors 603


    Feb 6, 2006
  9. rtrt, Feb 16, 2008
    Last edited: Aug 13, 2011

    rtrt macrumors 6502a

    Jan 19, 2008
  10. Rodrigo Lima macrumors newbie

    Feb 16, 2008
    4MOT/2/40000004: EXHAUST

    Does anybody know what is this and how I can fix that problem???

    Fan Speed:

    hard drive: 500rpm
    exhaust: 2798rpm
    power suply: 648rpm
    CPU fan: 2761rpm

    SMC version: 1.15f3
  11. GregPacker macrumors member


    Jun 27, 2007
    Wherever there is a queue
    The second 2008 mac pro that I had (and returned for graphics freezing) had something resonating at the top of the machine, perhaps the case itself. I found that simply putting a heavy book on top of the machine halved the volume of the whirring sound. Often computers resonate somewhere, and by pressing in different places on the case you can track it down and then do something to apply pressure to that area. My G4 MDD powermac had a side panel that resonated with the hard disks, until I stuffed something between the side of the case and the wall to keep some pressure on it.
    Often the resonating sounds are the ones that come and go apparently randomly, but this is probably due to slight distortions of the case from temperature changes, or the computer being moved or twisted slightly etc. Just reseating hard drives can often help.
    The fan pulsing sound may be due to a fan not being perfectly balanced or straight, making its axle kind of "process" in circles much slower than the actual rotation speed (a bit like how the tip of a gyroscope walks along a table in small slow circles). Or it may be an acoustic phasing issue caused by two fans where one is running very slightly faster than the other. I seem to remember hearing of someone solving their two fan phasing noise by slowing one fan down slightly by sticking some blue tac (a brand of the stretchy stuff you stick posters onto walls with) on its blades to make it heavier than the other one. Once the speeds are sufficiently different you don't hear the phasing.
  12. Col127 thread starter macrumors 6502

    Sep 13, 2003
    hmmmmmm.. i wonder if this is normal for everyone - i find the noise quite bothersome. my old powermac g5 was MUCH quieter than this mac pro; maybe i'll give apple care a call. my mac exhibits the reboot from sleep problem too. this is quite disappointing considering how long i had to wait for my mac to arrive since i ordered it......
  13. Infrared macrumors 68000


    Mar 28, 2007
    What thermal sensor readings are you getting?
  14. Rodrigo Lima macrumors newbie

    Feb 16, 2008
    Thank's for your reply... but what do you mean with thermal sensor readings? Temperature? This is what I could see with IStat Pro:

    CPU A 38º
    CPU A 28º
    CPU B 40º
    CPU B 28º
    Ambient 25º
    Northbridge 38º
    Expansion Slots 29º
    HD Bay 1 26º
  15. Rodrigo Lima macrumors newbie

    Feb 16, 2008
    HD Bay 2 31º
    HD BAy 3 31º
    HD Bay 4 32º
    Mem Bank A1 30º
    Mem Bank A2 31º
    Mem Bank A3 32º
    Mem Bank B1 30º
    Mem Bank B2 30º
    Mem Bank B 32º
    Mem Module A1 45º
    Mem Module A2 37º
    Mem Module B1 126º
    Mem Module B2 126º
    Power Suply 1 52º
    Power Suply 2 55º
    HD local 40º
    HD1 45º
    HD2 46º
    HD3 46º
  16. Rodrigo Lima macrumors newbie

    Feb 16, 2008

    Don't need to answer again my friend. I've pulled out this two burning memories and found the x of the question...
    thanks for all
  17. bpjauburn macrumors newbie

    Jan 16, 2007
    I'm a Mac newbie as I just switched from PC and got the MP on Monday. Last night I put in to 750GB Spinpoint F1 drives and after restart the two front fans turned on full blast and would not go off. I ended up shutting it down and after rebooting they were off and remained off overnight. The MP awoke from sleep this morning perfectly and the fans remained off.

    What I would like to know is

    a) how did you find the error code? Again, I'm a newbie so i don't know how to do much of anything.
    b) it looks like later in this thread you solved the problem. Could you tell me what you did?

  18. snagitseven macrumors member

    Jan 12, 2008
    Open "" in Utilities folder (in Applications folder). Look in "Console Messages" and "system.log". You can see everything your Mac has done or is doing. This is an indispensable diagnostic tool when things are not working properly. There are also many other logs available to peruse. Most logs will be undecipherable to most of us but many can point you in the right direction to track down the cause of a problem.
  19. Rodrigo Lima macrumors newbie

    Feb 16, 2008

    At first, you can try to run the AHT (apple hardware test) that comes with your OSX installation CD. Press "d" while restarting to boot from CD. If it's a hardware problem, you will find an error code there... I've downloaded a widget called iStat Pro too. It's a nice tool to get computer's temperatures, fan rotation, disk usage...and it's free. I've supposed that my fans were at full blast because of memories B1 and B2 very high temperatures. After that, I've pulled out the burning memories. Everything becomes normal and quite. I was right. Then, I've put the memories back, just in case, to know if I was really right... attaching it carefully. For my surprise the problem has disappear. Until now. Happy again... Good lucky.
  20. fkane macrumors newbie

    Mar 24, 2008
    Hey, just a quick tip, moving my HDD from bay 1 to bay 3 made everything more quiet. Just to do with the acoustics I think, not fan speed etc. Try it and see,
  21. Eric2 macrumors member

    Jan 18, 2008
    Hi Col127.

    I’m having very similar problems with a new MacPro.
    I also get the 2\3 second very loud blast but this doesn’t bother me and I’m sure it’s normal, its the constant load whirring noise when’s its idle that concerns me. See my thread:
  22. Infrared macrumors 68000


    Mar 28, 2007
    With the new MPs you don't need the CD. Just boot from the HD
    and hold down D.
  23. Luis Ortega macrumors 6502a

    May 10, 2007
    Fetcham Surrey UK
    your exhaust and cpu fan speeds are way too high.
    all 4 of those should be in a very similar range.
  24. beige matchbox macrumors 6502a

    beige matchbox

    Mar 16, 2005
    Oxfordshire, UK
    My fans are as follows-

    Exhaust 599rpm
    CPU 500rpm
    PSU 599rpm
    HD/Explation 798rpm

    CPU is running at about 200% right now, admittedly I only have the 4-Core single chip machine so maybe the CPU fan doesn't have to move so much air, but still, 2700rpm is pretty high, i've not managed to get mine passed 1000rpm when the CPU is at 400% :eek:

    Thinking about it though, I am in a pretty cool room, iStat is reading ambient at 19ºC and the CPU is at 31ºC, I'd guess the room temp is cooler still

    As to fixing the problem, i have no idea, sorry :eek:
  25. Rendition macrumors member

    Jul 1, 2007
    The graphics card having the full fan whirr for 2-3 seconds is perfectly normal.

    It has done that on my last 3-4 graphics cards on the PC for both Nvidia and ATI and also now on my new Mac Pro (2008).

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