PCI fan high revs when booting

Discussion in 'Mac Pro' started by kunia, Jan 18, 2011.

  1. kunia macrumors regular

    Oct 30, 2010
    The PCI fan on my 5,1 MP with 5870 revs up to about 2k rpm every single time I start my computer. Then it slows down to the regular 800...It sort of starts at about 2k and then over about a minute it slows down to regular levels.
    This started to happen about a month ago, and since I rarely shut down my computer (most of the times sleeps) I didn't really pay attention to it. I had gt120 in slot two for about a week now, but that revving (which is pretty loud at the beginning) was happening prior to that.
    Nothing (as far as I can tell) appears broken on the computer. The performance & video card performance is exactly the same as it was since day one, just the revving up during boot is somewhat new.
    Anyone with the same issue? It this normal?
    Should I reset SMC + pram/vram?

  2. Desmo1098 macrumors regular


    Aug 28, 2009
    I believe this is normal, and someone else might want to verify my response, but I think what is happening is a "self-calibration" of sorts. I would imagine there is a straight-line input with voltage, speed, and temperature. For example when the Mac Pro boots the card checks for 12V and checks the fan to 2000 RPM. Then once the boot process is completed it checks the temperature of the video card and it is probably at X which means X voltage which in turn equals X speed. Mine does this as well and I have no problems. Then as you begin to tax the video card by playing a video game, for example, the temperature, X, rises on the video card which increases the voltage to X which increases the fan speed to X.

    So in this case the voltage could be 5V which is equivalent to 140F which in turn increases fan speed to 1400 rpm.
  3. goMac macrumors 603

    Apr 15, 2004
    I have a high spin up of my GPU fans for about 3-4 seconds when I turn on my machine. I do not have a minute long PCI fan spin up. This does not sound normal to me.
  4. Transporteur macrumors 68030

    Nov 30, 2008
    He's talking about the PCIe section fan, not the graphics cards fans. And considering that this is a new issue, and the fact that others don't have this issue (including myself although I've got a 2009 model), it is definitely not normal.

    kunia, try resetting your SMC. That should help.
  5. Desmo1098 macrumors regular


    Aug 28, 2009
    Oopps... Missed that. Sorry Kunia, if it is not the video card fan, but the PCI fan then follow what Transporteur said.
  6. philipma1957 macrumors 603


    Apr 13, 2010
    Howell, New Jersey
    I get a high speed spin for under a minute. and i have a fan in my gpu card that does it. I am guessing this is the fan the op means. try booting with no access panel. watch the fan spin up. should be the gpu fan
  7. kunia thread starter macrumors regular

    Oct 30, 2010
    I do have the standard video card rev up once I press the power button. But it's the PCI fan that's revving high at the beginning.
    It pretty much goes like this...
    Power button pressed
    Video card van revs high for about 3 seconds
    The chime happens, gray screen appears and the PCI fan starts revving up to around 2000 rpm in around 3 seconds, then it slowly starts to rev down
    I get past my login screen, get the desktop running - which from the gray background with apple logo and load icon takes around 10-15s - and I can see the PCI fan (smcfancontrol) at around 1700 or so and dropping.
    45s to about a minute into the login the PCI fan drops down to standard 800 or so.

    SMC is the first thing I'll do once I get home.

    btw, the video card fan and PCI fan when revving high sound different.
  8. Transporteur macrumors 68030

    Nov 30, 2008
    Ohhh, that behaviour I know. My Pro does that after a kernel panick (happend twice now in more than 16 months, good average :D), or sometimes after booting from Windows back to OS X.

    However, it does it once, then everything's back to normal.

    So yes, something might be wrong with your SMC settings. Reset and we take it from there.

    BTW: The slow decrease of the PCIe fan is in fact normal, other fans decrease their speed faster. I don't know the exact reason for that, though.
  9. kunia thread starter macrumors regular

    Oct 30, 2010
    I'll report back after SMC reset...in about 4 hours:)

    And, the 5870+GT120 combo is really nice. Didn't notice any glitches when moving windows between screes, but I don't do any video other than watching movies. Plus I also got GT120 plugged into my TV with HDMI adapter. Throwing the TV into the mix with just the 5870 would not only split the VRAM, but also be more expensive! (if going with apple adapters) - mdp to dual link dvi are 110$ in Canada...two of those is 50$ more than the video card! I didn't notice any extra noise and no temperature increases. Much appreciated feedback about the video card setup:p
  10. kunia thread starter macrumors regular

    Oct 30, 2010
    Update: After SMC reset, rev up still present. The revving up part happens exactly when the apple logo and loading icon show up.

    could it be smcfancontrol 2.2.2 - I did notify me that this version might not be compatible with my mac pro
  11. kunia thread starter macrumors regular

    Oct 30, 2010
  12. xgman macrumors 601


    Aug 6, 2007
    hmmm . . I get this now (didn't notice it before) when I hold down the option key and choose my windows drive to boot from, (then it starts) then it slowly goes away by the time windows is booted. I don't notice it on a boot to mac drive. No big deal really as long as it quickly stops, but it would be nice to know what mechanics cause this.
  13. kunia thread starter macrumors regular

    Oct 30, 2010
    Well...nothing appears to be broken on my mac. I would just love to know whats the reason behind the rev up. Revving up happens when I boot into OS X, didn't try windows (for the past moth didn't find any reason to boot into that sh#$t:)

    And the PCIe fan only starts to rev up at the apple logo with loading icon....
  14. 666sheep, Jan 19, 2011
    Last edited: Jan 19, 2011

    666sheep macrumors 68040


    Dec 7, 2009
    Did you try uninstall smcfan? Symptoms you've described seems indicate, that it's responsible for PCIe fan misbehaviour (you've said before that you're getting message about its incompatibility with your MP). When :apple: is appearing on screen, OS has loaded graphics drivers and starts loading other system software. Try to boot in Verbose mode and see what loads when fan starts rev up. It should give you an answer if it's smcfan. If so, that's why SMC reset didn't help.
  15. kunia thread starter macrumors regular

    Oct 30, 2010
    I'll give that a try, thanks.
  16. Mac Hammer Fan macrumors 6502a

    Mac Hammer Fan

    Jul 13, 2004
    I have a MacPro 2009 with the ATI Radeon 5870 and everytime I boot the PCI expansion bay fan runs at 2000 rpm. After 30 seconds it slows down to 800 rpm. I believe this is normal.
  17. Evil Spoonman macrumors 6502

    Jan 21, 2011
    My 2009 Mac Pro (4870) also does this. I'm not sure what fan it is, but some fan in there spins up for a few seconds (~5?) at boot. I assumed this was a fan test, which would be logical on a workstation... in the unending quest for stability, it makes sense to not boot the machine if the fan doesn't work.
  18. minifridge1138 macrumors 6502a

    Jun 26, 2010
    Same MP and same card. I get the 2K rpm fan at boot, but it goes back to a silent 800 RPM at the startup 'ding' sound. It's long gone by the time I see the apple logo.

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