Gigabyte RX 460 (4GB) + Mac Pro 5.1: only HDMI-out works

[StefanJohansson]

I got a Mac Pro 4.1, and have flashed it to 5.1

Replaced the original graphics card (GT120) with a Gigabyte RX 460 (4 GB version, https://www.proshop.se/Grafikkort/Gigabyte-Radeon-RX-460-OC-WF-4GB/2562561)

I simply cannot get the DP to get working, tried two cables to my Dell U2515H (DP-DP and DP-mDP) but the monitor says it gets no signal. However, the HDMI signal (HDMI-HDMI) works just fine.

Any idea why this happens?
Do I need to edit something in my settings?

I tried to enable/disable DP 1.2 on the monitor without success.

Runs the latest OS X 10.12.5

 

[Kris Kelvin]

I've tested the same card in my Mac Pro 2009 (flashed to MacPro5,1) and it worked flawlessly with an LG 34UM95-P over DisplayPort.

Does the display show up in System Profiler when connected with DisplayPort?

 

[OEMPT]

You probobly have your monitor setup wrong. You MUST disable DP 1.2.

I use the exact same card with 3 Dell U2515H monitors, 1 dp + 1 hdmi + 1 dvi. The moment I would turn on DP 1.2, I would get a blank screen and have to do a workaround to disable it. Sierra does not support "daisy chaining" which requires the DP 1.2 protocol, maybe only with High Sierra but that's to early now to confirm until later releases come out.

 

[StefanJohansson]

Thanks for replies!

@OEMPT - will disable DP and restart everything and see if it works. Are you also running OS X 10.12.5?

@Kris Kelvin - cannot check that as I have a black screen when DP-connected

 

[Kris Kelvin]

cannot check that as I have a black screen when DP-connected

Well, you could connect both HDMI and DisplayPort at the same time – or use Remote Desktop if you have a second computer. Where there's a will there's a way.

 

[StefanJohansson]

@Kris Kelvin
Do you mean "system_profiler" in Terminal?

 

[Kris Kelvin]

Do you mean "system_profiler" in Terminal?

Either that or launch the app "System Information" (found in /Applications/Utilities), and take a look at the entry Hardware -> Graphics/Displays.

 

[StefanJohansson]

With DP 1.2 disabled and a restart, the GPU works like a charm
Thanks a ton for your help!

@OEMPT Now I will buy a 2nd Dell U2515H monitor (or even two more )

 

[joebclash]

how do you disable DP 1.2 in sierra?

 

[StefanJohansson]

how do you disable DP 1.2 in sierra?

I disabled it on my monitor (Dell U2515H), in the monitor menu, i.e. not in Sierra.

 

[ActionableMango]

I tried to enable/disable DP 1.2 on the monitor without success.

With DP 1.2 disabled and a restart, the GPU works like a charm

Well, I'm confused. It didn't work the first time you disabled DP 1.2, but it did the second time?

 

[StefanJohansson]

Well, I'm confused. It didn't work the first time you disabled DP 1.2, but it did the second time?

For some reason yes... I don't know exactly how/why. Maybe the cable was not fully plugged in the first time. Anyway, now HDMI-HDMI, DP-mDP and DP-DP works perfect, so I am a happy owner of a RX 460-card

 

[RexyStef]

What's the link speed you get with the rx 460? in the OpenCL ocean waves and bandwidth benchmark I only get 1.50gb/s. also, do you see it under system profiler pic section or do u get the error also?

 

[h9826790]

What's the link speed you get with the rx 460? in the OpenCL ocean waves and bandwidth benchmark I only get 1.50gb/s. also, do you see it under system profiler pic section or do u get the error also?

Ocean waves is not consistence, simply close it and open again may show a significant different number.

 

[periergos]

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Hi! Does your card run on Mojave?