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

StefanJohansson

macrumors newbie
Original poster
Jun 27, 2017
12
3
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
 
Last edited:

Kris Kelvin

macrumors regular
Dec 28, 2005
217
127
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?
 
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OEMPT

macrumors newbie
Nov 9, 2015
15
6
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.
 
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StefanJohansson

macrumors newbie
Original poster
Jun 27, 2017
12
3
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 :)
 

StefanJohansson

macrumors newbie
Original poster
Jun 27, 2017
12
3
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 :) )
 
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StefanJohansson

macrumors newbie
Original poster
Jun 27, 2017
12
3
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 :)
 
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RexyStef

macrumors newbie
Apr 4, 2017
5
4
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

macrumors G5
Apr 3, 2014
12,776
5,585
Hong Kong
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.