PCI and PS Fan Speed issue with 2 video cards

Discussion in 'Mac Pro' started by usna92, Jul 24, 2017.

  1. usna92 macrumors member

    usna92

    Joined:
    Mar 16, 2011
    Location:
    Seattle
    #1
    First, for the search minded for all of you I have read the following threads:
    https://forums.macrumors.com/threads/2009-mac-pro-fan-control.2057079/
    https://forums.macrumors.com/thread...ntrol-1-4-8-1-totally-out-of-control.2055699/
    https://forums.macrumors.com/thread...ems-with-non-apple-video-cards.1685629/page-2
    https://forums.macrumors.com/threads/7950-mac-edition-fan-speed.1566964/page-2

    Here is my situation. I have the following video cards. I have XFX 8GB RX-480, a Diamond Sapphire R9-280X, a GT-120, and AMD 5770 (The last two are Apple Branded). The RX-480 had been running in my PC machine, but I wanted to get the improved performance on my Mac Pro. Previous my MacPro has been running the R9-280X without issue. I got the GT-120 from work for free and I decided that boot screen might not be a bad idea, since I was considering adding BootCamp to this machine.

    First Setup:
    RX-480 and GT-120. No issues on Boot, all screens as expected, fan behavior normal. Machine went to sleep, pressed keyboard for wake, PS and PCIE fans go to max.

    Second Setup:
    RX-480 and 5770. Same Result.

    Third Setup:
    Reverted to R9-280X and GT-120 and got the same result. Can't do the obvious 4th setup because the 5770 and the R9-280X require too many onboard PS connections.

    So a couple of questions and then a proposed course of action to see if there are any better suggestions. I am running Mac Fan Control because my processors are upgrade to 5680s. I don't mind running the software, I just want to make sure this isn't happening because I am actually melting something that I can't measure. Also of note, while the fans are at max and before they go to max speed, there is nothing really out of the ordinary with temperatures. I don't understand why having two video cards suddenly freaks out the SMC, other than the empirical evidence of that it happens. I have reset NVRAM and SMC.

    So advice I am looking for?
    1. Is there a best configuration of two of these cards in particular slots that makes the most sense? The ideal setup would be the RX-480 the GT-120 since it preserves the most PCIe slots while still giving me boot screens, etc. Theoretically, it would also produce less waste heat than other options.

    2. Are there particular slots that might offer better results than what I am getting now?

    3. Is the XFX RX-480 card just going to cause me heartache (I know there have been issues with these cards before) and I should move on to a different combination in the interim (keeping in mind I still have the issues with the other two combinations).

    4. If the only way to make this work is Mac Fan Control, what should I take the PS and PCIe measurements from and what are the ideal settings?

    5. Are there other PCI issues or hard drive configurations that should be considered that might reduce stress/temperatures that could be affecting this issue? I currently have both optical drive bays filled, and 3 of 4 hard drive bays. I have a PCIe storage card for an SSD, a USB-3/C PCIe card, and the two video card combination currently under discussion.

    6. Why doesn't this seem to come up more in discussion with people using one or more video cards, or is this one of those solved issues that everyone (other than me apparently) has seen before?

    As always, any help comments, etc. would be great!
     
  2. ActionableMango macrumors G3

    ActionableMango

    Joined:
    Sep 21, 2010
    #2
    It could be the SMC firmware bug that Scottish Captain found. You can confirm by running a graphics accelerated application after the fan speeds are running at max. If running the application fixes the fans, then it is the SMC bug. If not, then something else is going on.
     
  3. h9826790 macrumors G3

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #3
    1) If you want RX480 and boot screen. GT120 is the way to go, no better option.

    2) try GT120 in slot 1 and RX480 in slot 2 to see if still the same result.

    3) XFX card know to be problematic, but I don't it's the root cause in your case.

    4) correct, no other fan control software has this ability because overriding the system can setting may cause over heat. MacsFanControl is powerful, in other words, danger (if improper use).

    My suggestion, PCIe fan base on PCIe ambient. PSU fan base on PSU 2 temperature.

    5) AFAIK, not in general, yours case is 99.99% GPU related, not from other source.

    6) because it's nothing to do with multi GPU, but installing a non Apple GPU. In fact, even you only install the RX480 may have the same problem.
     
  4. Squuiid macrumors 65816

    Squuiid

    Joined:
    Oct 31, 2006
    #4
    Would this work in BootCamp though?
    Do NVIDIA's and AMD's drivers happily coexist in Windows?
     
  5. usna92, Jul 24, 2017
    Last edited: Jul 24, 2017

    usna92 thread starter macrumors member

    usna92

    Joined:
    Mar 16, 2011
    Location:
    Seattle
    #5
    As always h98 you have good advice. Found some other things.

    1. Agree that this is the best configuration.
    2. I was getting the same result regardless of which two card setup that I used, so I am guessing its the stupid SMC bug (hopefully we actually get a firmware update when all the goodies ship with HS, but probably not.)
    3. This is the big one. Turns out under high load (WoW in Stormwind at the auction house) that the XFX card draws enough spike power to trigger SMC power shutdown. (Some serious BS with AMD creating that first reference spec that didn't catch this) This is a first gen RX-480 based on reference with 6 pin power and whatever special sauce XFX put in it. Ran fine in an external GPU, but apparently the sensitive backplane on the cMP is not having it, which really forces my hand as to which setup I am going with.
    4. Agree completely, which is why I have been using the settings you recommend for CPU, etc. when I changed those out, but this is my first experience with PCIe and PS settings. Right now for PCIe Ambient I have it set at 30-55 and PS at 28-50. Probably a little conservative, but I wanted to see how the system responded.
    5. Also agree GPU related. Without the GT-120 added the R9-280x was rock solid. I just wanted to reduce my power thermal curve a little. I guess I will have to wait for the stupid miners to move on, then grab a RX-580 with better behaved backplane performance.
    6. Well the RX-480 has other issues, so it won't go it alone, but I suspect it has to do with power draw of the cards over the bus. I have gotten really good at swapping videos cards. Tomorrow when I am working I may go back to automatic control of PS/PCI and let the machine sleep to see what happens on wake. I think the SMC is probably just freaking out over peak current across the slots on wake from sleep.

    Let me know if you think I have missed anything or there is something else I should tweak.
    --- Post Merged, Jul 24, 2017 ---
    I think the trick with windows is making sure whatever game (I am assuming for gaming) runs through the high performance card, rather than just picking one and rendering that to your display. I have an internal NVIDIA card on a laptop that I connect to an external GPU running an AMD card. When I only one at a time, windows figures it out pretty well. YMMV when running two at once.
    --- Post Merged, Jul 24, 2017 ---
    I will check for this tomorrow. If it is the SMC bug, is there really anything to do other than what I am already doing with Fan Control?
     
  6. h9826790 macrumors G3

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    Your setting is fine. Yes, it's consecutive, but nothing wrong. I personally prefer about 36-58 to keep the fan noise a bit lower, but it's really very personal. I am happy to let the PSU run at about 43C under high load (ambient about 33). If your ambient is low, and want to keep everything cool, your setting is actually pretty good.
     
  7. ActionableMango, Jul 25, 2017
    Last edited: Jul 25, 2017

    ActionableMango macrumors G3

    ActionableMango

    Joined:
    Sep 21, 2010
    #7
    If you confirm that it is this bug, then here are the two best single posts on the topic if you want to know more (the entire threads are worth reading IMHO, not just the two posts):

    https://forums.macrumors.com/thread...thout-fan-issues.1694103/page-2#post-18631695

    https://forums.macrumors.com/thread...use-expansion-fan-revs.1908705/#post-21729173

    Some people fixed the problem by moving their GPU to slot 2. I don't know how that would work with your two GPU system.
     
  8. Squuiid macrumors 65816

    Squuiid

    Joined:
    Oct 31, 2006
    #8
    ActionableMango, thanks for these.
    This is way out there but has anyone had the issue with just PCIe devices and no SATA (other than DVD-ROM)?
     
  9. ActionableMango macrumors G3

    ActionableMango

    Joined:
    Sep 21, 2010
    #9
    I don't remember. @ScottishCaptain knows the most--he even discussed the issue with Apple engineers.
     
  10. xactoman macrumors member

    Joined:
    Jul 9, 2015
    #10
    I have a GT120 and a GTX 1080 installed. Temp goes up as all drive bays are full and the Mac sees the extra heat and power draw and turns up the fans. It was much worse when I had the GTX 980ti instead of the 1080. To get the fans down to normal you just need to remove some items if you can. Something is pulling the power up.

    As for windows 10 drivers, I had to choose to install drivers for the 1080 only. There was a driver conflict with the GT120 even though it was nvidia. In order to get it to work, I had to let it run as a generic windows device. Nvidia then only configured for the 1080. I had no problems when I had the GTX980 and a ATI 2600HD installed. Both had their drivers.
     

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