Wont boot with 4K monitor

Question

Wont boot with 4K monitor

Mid 2012 Mac Pro tower.

Aftermarket R9 280X graphics card flashed with the correct EFI firmware (fully utilised and recognised by the Mac).

I got my new 4K monitor today. When I boot the Mac the grey screen appears just after the chime. However no apple logo appears and the second half of the chime plays constantly in a loop until I pull the power chord out or hold down the power button. If I boot the Mac without the monitor connected and finally connect it once I know it has fully booted, I get a display and the full 4K resolution is available to me. The computer wakes and sleeps just fine.

What is wrong with my computer?

P.S. Connected via Display Port. DVI and HDMI does not support 4K@60hz on this card.

Mac Pro, OS X El Capitan (10.11.3), 6-core, 24GB RAM, R9 280X

Posted on Apr 22, 2016 10:42 AM

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Answer 1

Mar 10, 2017 3:34 AM in response to Community User

Did you end up buying a different GPU?

I'm having the same problem with my Mac Pro 5,1 and the flashed R9 280X. I managed to boot via DP without problems (incl. bootscreen) when limiting to 4K @ 30Hz by switching from DP 1.2 to DP 1.1 directly on my monitor. It's still annoying since I have to change settings on my screen every time.

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Answer 2

lllaass

Level 10

210,411 points

Apr 22, 2016 10:55 AM in response to Community User

What specific monitor?

Does it boot OK when connected to another monitor via DP?

Have you tried:

- Try resetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

About NVRAM and PRAM

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Answer 3

Apr 22, 2016 10:57 AM in response to lllaass

BenQ BL2711U

The Mac boots fine over Display Port. My previous monitor was a Dell U2711 (2560x1440). I've just reset the PRAM and it didn't help.

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Answer 4

Apr 22, 2016 2:00 PM in response to lllaass

As it turns out, the DVI cable I was using wasn't a DVI-D cable. I've tried DVI-D and it now runs 4k and boots perfectly with no issues.

However it does only run at 30hz, which is a tad annoying. Will the Apple Mini Display-Port to DVI adapter do the trick?

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Answer 5

eludwig

Level 1

24 points

Apr 22, 2016 2:39 PM in response to Community User

The monitor spec page says:

3840x2160at 60Hz(DP, HDMI-2)

3840x2160at 30Hz(DVI, HDMI-1)

So DVI looks limited to 30Hz. Can you just use a MiniDP to DP cable?

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Answer 6

Apr 22, 2016 2:17 PM in response to eludwig

Display port is what causes the boot loop.

Since it uses a slightly older DVI standard I guess I'm stuck at 30hz. Does Apple or someone else do a DP to HDMI 2 adapter you can suggest which supports 60Hz?

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Answer 7

lllaass

Level 10

210,411 points

Apr 22, 2016 2:39 PM in response to Community User

http://www.j5create.com/our-products/displayport-adapters/jda158.html http://www.amazon.com/Club3D-Mini-Displayport-HDMI-CAC-1170/dp/B0194F1MPI/

http://www.moshi.com/cable-audio-video-adapter-mini-displayport-to-hdmi-4k

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Answer 8

Apr 22, 2016 2:39 PM in response to lllaass

I've looked at the Moshi one before but its only 30Hz.

Youtube videos shows the Club3D adapter working (with windows at least), so I've went for that.

Thanks 🙂

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Answer 9

Apr 23, 2016 12:23 AM in response to Community User

Okay so I just fire off an email to someone who knows these graphics cards like the back of his hand.

Its a problem with all flashed R9 280x cards. I either run an unflashed card or don't output 4K over displayport. So it looks like I'll be buying a GTX 970 instead. If I can't have a boot screen I may as well have a much faster card.

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