Mac 1080 Display port problems

dmay

macrumors newbie
Original poster
Jul 13, 2017
10
1
Hi all, had some great responses last time to some GPU related issues so was hoping to strike gold twice.

I've got a Mac NVIDIA 1080 as purchased from Macvid cards a few months ago. Aside from a few teething issues its running fine in my beefed up Mac Pro 2010. Had been using it with HDMI for a while but have recently got a new Samsung 4K U28E590 to use as a 2nd monitor. Only problem is, Display Port out on the card doesnt seem to be working at all.

When I have a monitor plugged in with HDMI it displays fine, but only if I have the HDMI plugged in before the machine boots up. If I try and plug a 2nd monitor into one of the 3 x DP slots, no dice. Similarly if I try DP with no other monitor in HDMI it wont work either. Wondered if it might be the DP cable Im using, but have got a DP - HDMI and a 4K rated DP - DP cable and cant get a picture with either of them.

Was wondering if anyone here has ideas on how to fix the 1080's display port issues? From doing a quick google it seems like there are some definite issues with DP on these cards. Such a shame it has 3 x DP and only 1 x HDMI otherwise I'd be able to work around it.

Thanks!
Dave
 

h9826790

macrumors G5
Apr 3, 2014
13,995
6,611
Hong Kong
1) Avoid DP - HDMI cable, it often cause issues.

2) If your monitor has DP setting, try DP 1.1 instead of DP 1.2

3) If you tested it with multi monitors and cables, and none of them work. You better contact MVC.
 

dmay

macrumors newbie
Original poster
Jul 13, 2017
10
1
1) Avoid DP - HDMI cable, it often cause issues.

2) If your monitor has DP setting, try DP 1.1 instead of DP 1.2

3) If you tested it with multi monitors and cables, and none of them work. You better contact MVC.
Thanks mate. Changed the DP setting on the monitor, no effect unfortunately. I'll buy another DP cable tomorrow just to be sure, but looks like it's the GPU. Unfortunately MVC just dont seem to respond to emails so dont really know what my options are.
Will be pretty annoyed if I just spent $1K on a GPU that only lets me do HDMI...
 

ActionableMango

macrumors G3
Sep 21, 2010
9,510
6,750
I'll buy another DP cable tomorrow just to be sure, but looks like it's the GPU.
Be careful which cable or adapter you get. Many common and highly rated cables pass through all pins, including pin 20. These are non-compliant cables. DP is not supposed to pass through pin 20. Doing so puts voltage where it is not expected, and can not work or even cause damage.

I have seen 3-4 examples just here on MR where a highly rated mDP cable, DP cable, or related adapter won't work. A replacement cable that is compliant does.

Read this thread for more information about the problem, and a link to a different brand cable that works:
https://forums.macrumors.com/threads/mini-displayport-curiosity.2034700/#post-24350267

Another recent example:
https://forums.macrumors.com/thread...port-apple-cinema-display-not-working.2057429
 

dmay

macrumors newbie
Original poster
Jul 13, 2017
10
1
Be careful which cable or adapter you get. Many common and highly rated cables pass through all pins, including pin 20. These are non-compliant cables. DP is not supposed to pass through pin 20. Doing so puts voltage where it is not expected, and can not work or even cause damage.

I have seen 3-4 examples just here on MR where a highly rated mDP cable, DP cable, or related adapter won't work. A replacement cable that is compliant does.

Read this thread for more information about the problem, and a link to a different brand cable that works:
https://forums.macrumors.com/threads/mini-displayport-curiosity.2034700/#post-24350267

Another recent example:
https://forums.macrumors.com/thread...port-apple-cinema-display-not-working.2057429
Great news, looks like it was indeed a cable issue.

I bought 3 more display port cables and got 2 of them working. So looks like about a 50% strike rate. So relieved there isn't anything wrong with the card.

For future reference to anyone who experiences a similar issue, Display Port DP cable not working on a Mac Pro NVIDIA 1080 can be solved by trying a bunch of cables. I had 2 different cables not work but then had a result with cables 3 and 4.
 
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