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Displayport and Ultrawide leaves black screen/no signal

echelon4

macrumors newbie
Original poster
May 3, 2014
15
0
I picked up a Mac Pro 2012 with a fresh High Sierra install. It has a flashed Radeon R9 280X 3gb (2x Mini DP, HDMI, DVI) video card installed.

I'm hoping to have 2 displays attached (neither scaled or using adaptors). First is a Dell 1920x1080 (rotated 270 degrees) and it works fine with a Mini DP/DP cable, though the screen does not rotate until after log-in and I can live with that. The other display is a LG 2560x1080 ultrawide display and only produces a black screen with a Mini DP/DP cable. It seems to be recognized but nothing is displayed. I get some scaled resolutions through DVI, but not the native 2560x1080. I do get 2560x1080 with a HDMI cable but I'm hoping to use displayport.

Any ideas? I've read issues with Sierra/High Sierra and scaled resolutions, but I'm avoiding them. Thanks!
 

h9826790

macrumors G5
Apr 3, 2014
14,505
7,034
Hong Kong
I picked up a Mac Pro 2012 with a fresh High Sierra install. It has a flashed Radeon R9 280X 3gb (2x Mini DP, HDMI, DVI) video card installed.

I'm hoping to have 2 displays attached (neither scaled or using adaptors). First is a Dell 1920x1080 (rotated 270 degrees) and it works fine with a Mini DP/DP cable, though the screen does not rotate until after log-in and I can live with that. The other display is a LG 2560x1080 ultrawide display and only produces a black screen with a Mini DP/DP cable. It seems to be recognized but nothing is displayed. I get some scaled resolutions through DVI, but not the native 2560x1080. I do get 2560x1080 with a HDMI cable but I'm hoping to use displayport.

Any ideas? I've read issues with Sierra/High Sierra and scaled resolutions, but I'm avoiding them. Thanks!

If the display support above DP 1.2, try set it to DP 1.2 or 1.1.
 

orph

macrumors 68000
Dec 12, 2005
1,884
392
UK
i think it will work over DVI as long as it's a "dual link DVI cable" and "dual link DVI port" at 2560x1080.
https://en.wikipedia.org/wiki/Digital_Visual_Interface
dual link DVI max rez 2560 × 1600 @60hz (single link is only 1920x1200)

so if you have a pile of DVI cables worth a look to see if you have a dual link one

DP is a better tho if you can make it work (is it higher bit depth and refresh rate ?)
 

echelon4

macrumors newbie
Original poster
May 3, 2014
15
0
@h9826790 - I'm not sure how to change display support, I don't see it any setting (LG 29UB55-B).

@orph - The cable I tried is DVI-I Single Link. I currently use it on my 2008 Mac Pro @ 2560x1080.
 
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