Mac Pro 5,1 refusing to load with hdmi connected - new GPU

Discussion in 'Mac Pro' started by jtyh1g11, May 21, 2019.

  1. jtyh1g11 macrumors newbie

    May 16, 2019
    Hi guys,

    Newbie here!

    Hoping I can get some advice!

    I've got a mac pro 5,1 2012 and I've just installed an msi radeon rx 560 4gb graphics card, ready for upgrade to Mojave.

    I've got a 4k monitor which I was using on hdmi without any problems on my last card, now it seems the mac only boots with the hdmi disconnected - I have to plug it in later.

    If the hdmi is connected on launch, the start tone just keeps repeating and mac refuses to load.

    I've tried on a smaller BenQ monitor (hd ready) which seems to load fine! Really don't know what's going on here!

    Any help/advice would be greatly appreciated! Thanks! :)
  2. bookemdano macrumors 65816

    Jul 29, 2011
    I would try clearing your NVRAM (use a USB keyboard, when you hear the boot chime hold down Command+Option+P+R and keep them held down through three or four cycles--you should hear a boot chime for each cycle). Then let go and see how it goes.

    Do you know if your 4K monitor uses HDMI 2.0? If not, then you shouldn't use HDMI anyway because older versions of the HDMI spec could only do 4K resolution @ 30Hz.

    Does your monitor have DisplayPort? If so, can you try connecting it that way instead?
  3. jtyh1g11 thread starter macrumors newbie

    May 16, 2019
    Thanks very much for your reply!

    Ah interesting, I didn't know that about HDMI, my monitor/tv specs does say HDMI 2.0 however. I picked up DisplayPort cable today so will give that a go too. :)
  4. bookemdano macrumors 65816

    Jul 29, 2011
    Good to have a DP cable around, if only for troubleshooting purposes. If your monitor has HDMI 2.0 then it should be fine to display 4K @ 60Hz, since the HDMI connection on the AMD 560 is also HDMI 2.0.

    Let us know how it goes. Do try the NVRAM reset if you haven't already.
  5. jtyh1g11 thread starter macrumors newbie

    May 16, 2019
    I've given the NVRAM reset a go, which hasn't seemed to have done anything, the startup tone still repeats indefinitely. I've also tried a DVI to HDMI cable and have the same problem with this.

    Would it matter if the displayport cable is displayport to hdmi? I ask as my monitor/tv doesn't have a displayport port.

    Again, thanks for your help, you're awesome! :)
  6. bookemdano macrumors 65816

    Jul 29, 2011
    Yeah I still think it's worth trying one of the card's DP outputs even if it still gets converted to HDMI on the monitor side. Although, sounds like you already tried the DVI output with no change. Does your monitor only have one single HDMI input?

    You could check the monitor's menu to see if there are any settings that relate to its HDMI input you could try tweaking. If it has the option to toggle the HDMI port to HDMI 1.4 that would be worth trying (but crappy as a fix because it limits you to 30Hz at 4K resolution).

    Is this the MSI Gaming Radeon 560?
  7. jtyh1g11 thread starter macrumors newbie

    May 16, 2019
    I'll hopefully get a DP>HDMI lead tomorrow and give it a go! My TV has 3 hdmi ports, all of which I've tried, with the same outcome.

    Yes it is the MSI Gaming Radeon 560 - which other people seem to have got working with macs and 4k screens.

    I've checked all through the HDMI settings and there don't seem to be any setting relating to HDMI input.


    ps. I suppose maybe an HDMI switch would be a 'workaround', having it on an empty input till it's got past the startup tone then switching to the live input. Not sure if that would work...?
  8. bookemdano macrumors 65816

    Jul 29, 2011
    I don't know either. Make sure if you get one to try though that it advertises HDMI 2.0 compatibility. You could also see if booting up with the TV switched off works (then you could switch it back on after boot).

    One other idea just for grins--can you connect your Benq monitor via DVI or DP and then the 4K monitor via HDMI and boot with both monitors connected simultaneously just to see if it still freezes up?
  9. jtyh1g11 thread starter macrumors newbie

    May 16, 2019
    I tried having both monitors plugged in which still for some reason didn't work - had the same repeating startup tone error.

    I've essentially got around the problem by plugging the monitor into an extension cable with a switch on it. I only flick the switch and power on the monitor once the startup tone has 'bonged'. It's not 100% ideal but it's a decent enough fix!

    Thanks very much for taking the time to help me out, it's very much appreciated! :D
  10. bookemdano macrumors 65816

    Jul 29, 2011
    Sure thing. Glad you found a workaround that's not too annoying.

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9 May 21, 2019