No HDMI video with new Ultrawide Monitor

buster84

macrumors 6502
Original poster
Oct 7, 2013
392
133
I purchased a new x34 predator monitor for use with my gaming PC, but i also have my mac pro next to my gaming pc since i share monitors. I can get hdmi to work with my PC and laptop, but i get no video with the mac pro.

The mac pro is fully updated in latest software and running the original amd 512gb video card that came with it. I am able to get a video when i connect my mac pro to my old 27 monitor (the one i replaced the new one with) but im unable to get my mac pro to output any video to the new monitor, it acts as if it cant detect the monitor. I'm also using a dvi to hdmi adapter since the raideon card doesn't have an hdmi port on it.

I tried a pram and smc reset and neither worked, tried multiple hdmi's and still nothing.
 
Last edited:

ActionableMango

macrumors G3
Sep 21, 2010
9,263
6,249
But shouldnt it at least detect and run at a lower resolution like 720 or 1080p?
You would think it would do something smart like that, but when I tried to use a single-link DVI cable for 3440x1440/60 it resulted in colored snowy garbage. Switching a dual-link DVI cable or DisplayPort fixed it. So I think different monitors handle it in different ways.

In any case, you wouldn't want to run in 1080p would you? You'll still need a DP or mDP cable for running the proper resolution anyway.

If you do get a new DP/mDP cable, make sure it doesn't pass through pin 20. Those can cause problems:
https://forums.macrumors.com/threads/mini-displayport-curiosity.2034700
 

buster84

macrumors 6502
Original poster
Oct 7, 2013
392
133
You would think it would do something smart like that, but when I tried to use a single-link DVI cable for 3440x1440/60 it resulted in colored snowy garbage. Switching a dual-link DVI cable or DisplayPort fixed it. So I think different monitors handle it in different ways.

In any case, you wouldn't want to run in 1080p would you? You'll still need a DP or mDP cable for running the proper resolution anyway.

If you do get a new DP/mDP cable, make sure it doesn't pass through pin 20. Those can cause problems:
https://forums.macrumors.com/threads/mini-displayport-curiosity.2034700
Thanks for the info, since i use the mac as a guest computer/video editor I've decided that swapping DP cords just to go from mac back to PC would be annoying and DP A/B box's are around $60-$80 so i'm just going to save the cash and trouble and set up the mac in another room with the other monitor.

I'll definitely keep your advice in mind about the DP cord if i ever upgrade the cord route.