Question for MVC (Cinema Display)

Discussion in 'Mac Pro' started by Demigod Mac, Mar 25, 2015.

  1. Demigod Mac macrumors 6502a

    Apr 25, 2008
    Hey MVC,

    I noticed in some of your screenshots that it says Apple Cinema Display.
    I'm assuming that's the 2008 model, 24" 1920x1200 res, which is what I have.

    Have you ever tested it on one of your 780 GTX 3GB (rev.A)?

    I have an issue where if I leave the ACD connected and boot, the bootscreen has a sparkly rainbow pattern, then the Mac hangs, fans go high RPM and won't proceed any futher. But if I disconnect the displayport cable, boot, wait for the chime, and plug back in it works perfectly. Issue also happens in Single User Mode except it's a scrambled black/white screen.

    This only affects the Displayport output. Using a Startech DP->MiniDP adapter.
    Tested the card's HDMI output on my TV and it works fine, Apple logo + boot screen and all.

    Not a showstopper bug, card works great otherwise, just would be nice if I didn't have to unplug/replug the monitor every time I boot. Was wondering if you had any ideas how to fix it.

    Specs are:
    Mac Pro 5,1 (6-core)
    OS X Yosemite
    780 GTX 3GB rev.A (PNY Brand) vanilla reference cooler, used your mod service
    Happens on both OSX and Nvidia drivers

    Attached Files:

  2. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    Each and every Kepler/Maxwell card is tested with that exact display. I just moved my 30" Cinema Display into the "sell" category and put the Dell 5K where it was. (Functioning Dual-Link DVI not as important as it was 5 years ago)

    But my 2nd display on the 4,1/5,1 test machine is the 24" Cinema Display.

    We also test with Dell U2410 (has 1 of every port type, very versatile) and an Asus PQ-321Q and a 27" ACD with mDP. Also a couple Dell 24" with just DVI and an LG 60" Plasma 2K. I was just commenting to my assistant yesterday that while some displays may be moving out of office, we will be keeping the 2 Apple LED mDP displays for the foreseeable future as our cards need to be 100% compliant with these displays since they are common with our clients.

    I can state for a fact that every 780 that has left here was connected to my 24" ACD, not once but twice. Each card is tested once after EEPROM placement while partially assembled, then fully assembled and tested again with a full run of "Valley" at high settings. Typically this results in 2 checkmarks on back, though sometimes I get stupid and forget to make 2nd one.(or can't find marker)

    Your issue looks like poor connection somewhere. Nobody else has reported that I am aware of. If you are in LA it would be easiest to pin down, but most likely you aren't.

    So, have a close look at the Startech adapter. See if any pins look bent down or missing. My 24" is actually on an extension cable that carries mDP and USB. This tends to exacerbate signal issues. Do you have one of these?

    About 1/150 of the Startech adapters are flawed, they tend to lose sync or have noise when failing. It may be the adapter, your cable, the SPECIFIC card, or your display. Once we rule out the adapter we can track it down further.

    But I am 100% CERTAIN that the issue isn't with the rom itself. Have done a few hundred 780s and have never heard of this issue before. So, that is why I mentioned your SPECIFIC card as opposed to an issue with rom itself.

    Once you are certain STartech is fine, email me directly and we can work out further details. Will get to the bottom of it.
  3. Demigod Mac thread starter macrumors 6502a

    Apr 25, 2008
    I think you're probably right. Makes me think my ACD might be flawed in some way, so was curious if yours had the same issue. Tried 3 different brands of DP>MiniDP adapters but they all have the same issue.

    I really need to find a regular Displayport monitor to borrow and test. That'd narrow it down for sure.

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