cMP DisplayPort -> mini DisplayPort -> Apple Cinema Display Not Working

-VoiceOfReason-

macrumors member
Original poster
Apr 27, 2010
63
10
I have a 2009 Mac Pro 4,1 flashed to 5,1 and an Nvidia GTX 680 flashed with the Mac ROM.

I recently upgraded my monitor setup to two 30" Apple Cinema HD Displays and one 27" Apple Cinema Display (with mini DisplayPort and USB).

The two 30" displays are plugged into the two DVI ports on the 680 and work fine. For the 27" ACD, I ordered a male DisplayPort to female mini DisplayPort adapter (from CableMatters). I could not get the 27" ACD to come on at all for some reason. Previously I used this DisplayPort on the 680 with a DVI adapter to drive another triple monitor display without issue.

I was only able to get around this by installing the original Nvidia GT120 and using the mini DisplayPort port on that card, with which the monitor works fine.

Is there any way to get this monitor working on the GTX 680? Has anyone run into this before?
 

ActionableMango

macrumors G3
Sep 21, 2010
9,510
6,750

-VoiceOfReason-

macrumors member
Original poster
Apr 27, 2010
63
10

h9826790

macrumors G5
Apr 3, 2014
13,998
6,615
Hong Kong
That Cable Matters cable is non-compliant. They pass through pin 20, which is a no-no.

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
In fact, I just bought a male DP to female mDP adaptor few weeks ago. I totally forget about this pin 20 matter, and just pick the cheapest one on a China internet shop (about $2 including shipping). Luckily it work flawlessly with my ACD :p

It's a Chinese link, but I still post at here, just in case someone want to know how it looks like and get it on eBay / Amazon etc.

http://m.intl.taobao.com/detail/detail.html?id=525452622266
 

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