PCI and PS fan speed problems with non-Apple video cards

Discussion in 'Mac Pro' started by RumoredTone, Dec 17, 2013.

  1. RumoredTone, Dec 17, 2013
    Last edited: Jan 11, 2014

    RumoredTone macrumors member

    Nov 12, 2004
    Hello all,

    This is regarding a known issue with Mac Pro 4,1 and 5,1's, where installing certain video cards (usually non-Apple cards, but not always) results in improper system fan control. There are several threads from over the past year or so, making it hard to pick just one to respond to. I decided to start a fresh thread, but would encourage anyone who's interested in the topic to check out these previous discussions as well:


    I wanted to revisit this topic, to share some of my own observations, and see if there's been any new headway made toward understanding the problem. I recently purchased a new 2012 6-core model (built June 2013), an upgrade from my previous 2008 2.8 8-core (3,1). Among the components that were migrated to the new machine is an EVGA GTX 670 (with no EFI).

    I never had any unusual fan issues in the 3,1 but in the new 5,1, I've experienced fan behavior that's consistent with what others have encountered: the PCI and PS fans run well above their normal levels, and can vary wildly based on different factors. There are several variables that others have observed in the past that may affect this behavior:

    1. Whether it's an OEM Apple card (though some have reported problems using the Apple 5770 in 4,1's)
    2. Whether the video card has EFI (though some have reported problems with recent Mac Editions from EVGA and Sapphire as well)
    3. PCIe slot 1 vs. 2
    4. Drive configuration (SSDs vs HDDs and different combinations)
    5. For single-power cards, cable A vs. cable B (coinciding with slots 1 and 2)
    6. Cold starts vs. soft restarts/sleep

    Some folks also wondered if it was only 4,1's (or 4,1's with the 5,1 firmware hack). However, my machine is a brand new 2013-built 5,1, so that doesn't seem to be the case. There have also been some recent fan problems that are specific to Mavericks, which may or may not be related.

    My Observations

    My system has two SSDs in sleds 1 and 2. These are the main Mac and Windows boot drives. I have access to three video cards for this machine: the OEM Radeon 5770, an older OEM 5870, and the GTX 670. I did a variety of tests, and can provide specific RPM numbers if it's helpful, but I'll just stick to a summary for now. In general, the Apple cards (Radeon 5770 and 5870) both behaved in the way one would expect, with low system fan speeds at idle and no unusual ramping up under load. There are a few minor differences between the two, but nothing out of the ordinary. The Radeon 5770 was also fine using either power cable.

    With the GTX 670 installed, however, I observed the following:

    In slot 1, the PCI and PS fans run high after a cold start, but can be "fixed" with the graphics load trick (running the OpenGL Extensions Viewer benchmark). After this, the system fans settle down and seem to behave exactly as they should. This well-mannered behavior carries over through soft restarts (including into Windows) and through sleep/wake. A cold start reverts to bad behavior.

    In slot 2, the PCI and PS fans run slightly high, but closer to normal. The OpenGL Extensions Viewer trick has no further effect. One interesting oddity: installing a HDD in sled 3 drops the PS fan speed to normal (600rpm), but the PCI remains the same. Overall, having the video card in slot 2 would be acceptable for me if not for the fact that the fans still ramp up unnaturally high when the video card is under moderate to heavy load in Windows. Others have said that using slot 2 works around the problem, but in my case at least, it's only a partial workaround.

    A few other notes:
    - Booting from a HDD made no difference
    - Booting from a fresh installation of Mountain Lion made no difference
    - I have yet to try Mavericks


    So for me, the only way to get 100% correct behavior is to use slot 1 and the OpenGL Extensions Viewer trick after cold starts. The fans then run at their correct 800/600/600/600/856 speeds at low-load, and only increase slightly under heavy load. Based on all my observations, I'm inclined to think the problem is more about an error in power-sensing than heat-sensing.

    It actually makes me wonder about something I noticed when I first set this machine up. I ran the hardware test a few times, and it kept producing an error message related to a Power Supply sensor. After researching the error, I found that it was documented on the Apple support site, where they claim it's essentially a false positive:


    It may be entirely unrelated, but it does make me wonder. In any case, I hope this post is helpful. If anyone has any questions or other information they can share, please do. Thanks!
  2. riggles macrumors 6502

    Dec 2, 2013
    Thank you for this. I'll have to research the OpenGL extension test to see if that helps me. Just upgraded my 5770 to a GTX 670 4GB, and immediately noticed increased fan speed. iStat shows PCI fan idles at about 1,200RPM. Under small loads it ramps up to 2,000. Missing my quiet workstation already, but I need the memory and increased application performance I get.

    Edit: Will having it flashed by MVC fix such issues?
  3. ActionableMango macrumors G3


    Sep 21, 2010
    Thanks for bringing this all together. Here is another pretty good thread to add:

    Also, I don't think that first link you provided is related to the issue at all. I'd remove it.

    At least one person with the fan problem verified that he passed AHT with no errors, so I don't think it's your power sensor. Admittedly I would feel more comfortable saying that if it least one or two more people with the fan problem would run that test and report the same.

    Would I would really like to see in terms of troubleshooting is:
    (A) Someone with this problem try the video card in other MPs and see if the problem follows the video card to the other MPs.
    (B) Someone with this problem try other non-Apple video cards (or an Apple 5770) in his/her MP and see if the problem persists with drastically different cards.

    P.S. I cannot find the threads now, but I vaguely remember that there were people messing around with upgrading MPs to newer versions by physically replacing boards (2006 to 2008 I think), and also building a MP from scratch but with mismatched boards (2009 and 2010 I think), and both of these people had PCIe fans running at top speed. I'm not saying it's related, but I believe the SMC firmware controls the fan speed and in the MP it seems to be pretty damn finicky and/or prone to bugs.
  4. NOTNlCE macrumors 6502a


    Oct 11, 2013
    DMV Area
    Believe it or not, I am having the opposite problem. My EVGA GTX 660 OC (PC, 2GB Edition) runs nice and quietly under OS X, even under CUDA load in Premiere Pro, but when I'm running Windows for light gaming, it overheats. I'm yet to do it, but I think this could be solved by using the EVGA utility that came with the card, but I just think it's odd. I am on a 3,1 however, so it could be the system itself just not handling the OS, since Windows 8.1 is "unsupported" on my machine. Just pointing out what I've observed. Thanks for condensing the information.
  5. RumoredTone thread starter macrumors member

    Nov 12, 2004
    Thanks for the replies so far. I took 'Mango's advice and swapped in a better thread for the list of references (thanks!).

    Riggles, if you'd like to try the OpenGL Extensions Viewer "trick," you can download "OpenGL Extensions Viewer" from the App Store (it's free). When you run it, you'll see a "Tests" tab. Run the basic cube test, and you may find that your fans ramp up quickly during the test, and then settle down afterward, continuing to drop until they reach their correct base levels (around 800rpm for PCI and 600rpm for PS). Regarding your question about a MVC EFI flash, I couldn't say for sure. I don't recall MVC saying that he ever deciphered the problem, but I would be happy to be wrong! My best guess, though, is that it would not correct the problem (given that official Mac Editions from EVGA and Sapphire have issues). It would have other benefits though (boot screen, startup commands, full PCI 2.0 speed under Windows).

    ActionableMango (I've always loved your name!), I unfortunately only have access to my 2008 model for comparison, but I can say it had no problems with the 670 GTX, the Radeon 5870, or the original GTX 8800 that shipped with it. The only strange video card voodoo I noticed with the 2008 is that CUDA-Z reported reduced PCI link speed for the 670 GTX when running in slot 1. I'm not sure if it was true or just a reporting error, but I eventually moved it to slot 2 which cleared up the problem.

    NOTNICE, I never had trouble with the 670 GTX in my 3,1, though one comment I can make is: compared to this 2012 model, I feel like the video card fan was faster to ramp up than the system fans, when under load. It was clearly audible above the system fans. Maybe your video card's fan is not responding correctly?

    Thanks again!
  6. riggles macrumors 6502

    Dec 2, 2013
    OpenGL Extensions Viewer worked

    Well, that free OpenGL Extensions Viewer app worked. Previously, if I had my graphics card in slot 2, it could idle down to just over 1,000RPM, but never lower, even with the OpenGL app. In slot 1, boot up would send the card to 1,800-2,000. But, after running the OpenGL app cube test, it idled right down in ~30sec. to 800RPM. So it's just like you said: 600/800/600/600 even across the board.

    Fortunately I don't turn my machine off that often, just put it to sleep. So I won't have to do this all the time. Would love to never have to do it, but it'll do for now. Thanks again~
  7. ActionableMango macrumors G3


    Sep 21, 2010
    Riggles, I don't suppose you could run the Apple Hardware Test and see if you get the same error regarding the power sensor?

    Here is how to do it:
  8. riggles macrumors 6502

    Dec 2, 2013
    Sure, no problem. Will it show up on my display since I have a non-EFI graphics card?
  9. jenzjen macrumors 68000

    Aug 20, 2010
    My issue, had both 5770 and 5870 Apple eom cards with no fan issue. Went to a 7870 in slot 1, never heard the OpenGL trick but could not get fans to settle. Moved card to slot 2, still elevated fans but not as erratic as slot 1. Now after I use the machine in windows and sleep it here and there, fans go back to normal and persists thru soft boots into both OS X and windows. A shutdown and restart brings back elevated fans but solved by sleeping in windows. Sleeping the machine in OS X doesn't seem to work.
  10. ActionableMango macrumors G3


    Sep 21, 2010
    Good question. I have no idea. I've always had EFI cards.
  11. rk25123 macrumors regular

    Aug 17, 2010
    Same problem with a GTX 680 Mac Edition, the OpenGL trick seems to work. It's quite incredible to have this kind of problem with a graphics card specifically designed for the Mac Pro...
  12. RumoredTone thread starter macrumors member

    Nov 12, 2004
    I'm fairly sure an EFI video card is needed to run the hardware test. I ran my tests with all the stock components before upgrading anything. It's possible it may work without EFI if you have an Hardware Test disc to boot from for your machine.

    I was actually surprised to find that my 2012 model came with no optical media at all. It's not a big deal for me, since I already own a retail Snow Leopard package I could use in an emergency. But it seemed like it might be confusing to a new Apple user, if their Mac Pro's system software ever became damaged and unrecoverable, of if they just wanted to install to a new hard drive. They'd have no idea how to do a fresh install. I guess Apple expects the recovery partition to handle things, but that could be damaged too.
  13. riggles macrumors 6502

    Dec 2, 2013
    Yea, I had never run the AHT, so I did a quick Google search for screenshots… No OSX being loaded there for sure, haha. So I seriously doubt any drivers will have been loaded to get something on the screen with my non-EFI card. I'd put the stock 5770 in there, but that would defeat the purpose of the test.
  14. riggles macrumors 6502

    Dec 2, 2013
    Purring quietly

    Just as a follow-up. My GTX 670 4GB is running smoothly after that Open Extensions trick. I'm in Octane standalone right now rendering, GPU is at almost full load, and fan speed is just under 1,350RPM. Very subtle hum. Love it!
  15. donw35 macrumors regular


    Jul 3, 2010
    Los Angeles
    I have an PC GT240 card in my 1,1 and fan speeds normal and when some processing hits they spin up and back down when done, no different then when the 7300GT was in it.
  16. Stephen Dowling macrumors regular

    Stephen Dowling

    Jul 29, 2009
    New Mexico
    This is definitely a strange issue. I currently have a Mac Pro 4,1 flashed to 5,1 with an EVGA GTX 680 Mac Edition.

    When I first bought the machine, I immediately replaced the stock GT 120 with an EVGA GTX 660 Sig. 2 PC card and I didn't experience any fan issues at all. Now, what's funny is that a few months later I decided to sell the GTX 660 and buy an EVGA GTX 680 Mac Edition; After I installed the 680 and booted up, my PS and PCI fans went nuts.

    I didn't think too much of it at first; so I logged in and downloaded the nVidia web drivers (was on 10.8.5 at the time), shut down after they installed, reset SMC and NVRAM/PRAM, and the issue went away...until the next time I shut down and did a cold start the next day. I finally decided to use smcfancontrol to bring the PS and PCI fans down to normal speeds, and that's what I've been doing ever since.

    Also, the same thing happens when I boot into Windows 8.1; but after the initial speed-up at login, the fans simmer down to normal RPMS. However, I've noticed that sometimes the PS and PCI fans will randomly spin up regardless of hardware load. I can sit in front of my Mac Pro with everything closed except for Activity monitor showing 0% usage and out of nowhere the fans will spin up for anywhere in between 5-30 seconds, and then slow back down.

    Weird. :confused:
  17. ActionableMango macrumors G3


    Sep 21, 2010
    It would be interesting to watch Hardware Monitor while that is occurring to see if it is related one of the temperature or power sensor readings.

    Actually, it wouldn't defeat the purpose of the test as the power sensor is in the Mac Pro, not the video card.

    OP ran the AHT and found a power sensor fault in his MP. He speculated that maybe the faulty power sensor affects his video card fan speed. So if you ran the AHT, regardless of which video card you had, it would be helpful to see if your MP has the same power sensor fault.

    If you do, that points a big fat finger at faulty power sensors. If you don't, that rules it out.
  18. riggles macrumors 6502

    Dec 2, 2013
    Gotcha, my mistake. I thought it was to see if the non-EFI card was triggering a false positive and causing fan speeds to increase. Ok, I can run the test over the weekend and report back.
  19. JronMasteR macrumors 6502


    May 4, 2011
    I also have/had these issues. PCI and PSU fan idles at much higher rpm's until I put some load on the system.
    A very good solution, at least for me, is to use this fan control app:

    It's a great app, works perfectly and is available for Mac OS as well as for Windows via Bootcamp.
    For the PCI and PSU fan I just chose "Sensor based value". You can then set the temp value for when the fan should start to ramp up and the temp for when it should ramp up to its maximum. Works very well.

    Although, I do not recommend changing the booster and intake/exhaust fans to anything else than auto. If you do so, the fans will ramp up like crazy if you restart your mac.
    Since these fans behave normally, it shouldn't be a problem.
  20. riggles macrumors 6502

    Dec 2, 2013
    Couldn't get my machine to start in AHT mode, so I don't have any test results to give. Not sure why, I swapped in the original graphics card and unplugged all USB cables expect for the one to my Cinema Display. Oh well, OpenGL Extensions test works for me, so I'm buttoning up my machine for the winter.
  21. ActionableMango macrumors G3


    Sep 21, 2010
    Thanks for trying!
  22. riggles macrumors 6502

    Dec 2, 2013
    No problem. Oh, and when I said I'm buttoning it up for the winter, I spoke prematurely. I'm getting a 770 Classified 4GB in next week in anticipation of Octane render plugin for MODO, so it won't stay closed for long. Curious to see if the fan speeds will change much. Will both cards be displayed in iStats Menu?
  23. ActionableMango macrumors G3


    Sep 21, 2010
    I don't know. You should ask in one of the multi-card threads. I only run one card.
  24. ScottishCaptain macrumors 6502a

    Oct 4, 2008
    Sign me up for this issue.

    I've got a Mac Pro 2010 with a brand spanking new eVGA 680 GTX Mac Edition exhibit errant PCI-e and PSU fan speeds. This is pretty inexcusable for such an expensive machine (marketed as accepting PCI-e cards- not just Apple branded PCI-e cards). I'll be contacting eVGA and insisting they fix the problem, and I think you all should too. If anything we might get them to kick Apple in the ass and fix the SMC for a machine they are still selling in some cases.

  25. ActionableMango macrumors G3


    Sep 21, 2010
    It would be nice if someone with this problem could do the AHT to see if they have the same reported problem as OP (power supply sensor). The result would either confirm a theory or eliminate it.

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