Q: Third monitor wont work with Eyefinity anymore
-
Aug 12, 2016 2:05 PMby Grant Bennet-Alder,HelpfulDisplayPort and its small-sized but electrically-identical variant Mini DisplayPort and the implementation that is a Thunderbolt subset, all use differential (push-pull) signal drivers at very low voltages. They are MORE immune to noise than older methods because the signal is encoded on the difference between two signals, not one signal referenced to an "everybody" ground. If possible, you should connect all displays with [Full-size] DisplayPort or Mini DisplayPort. These put much less load on your system.
When you convert this very low level signal to a "legacy" display, the card runs out of ability to directly drive signal levels high enough to be recognized after connecting TWO legacy displays of any description. If you choose to use a supplied DVI or HDMI port directly, that still counts as one of your two "free" conversions. (It is also possible that a very fussy display will drop out even sooner).
Any "legacy" displays beyond the first two require ACTIVE adapters of some description. ACTIVE Adapters contain signal re-drivers, and are therefore more expensive that ordinary adapters. Typical prices are in the US$40 range, but some competition has lowered some prices slightly. Mini DisplayPort has a backward-comparability mode, requested by ordinary adapters, that can get it to produce a Single-Link DVI signal at up to 1920 wide, but an ordinary adapter does not boost the signal levels.
The Apple Mini DisplayPort to Dual-Link DVI, which is used for DVI displays wider than 1920 wide, is more complex and more expensive, and requires additional power beyond just signal re-drivers. This power is typically picked up from a USB pigtail, but the USB data are not generally used by the adapter, so a different USB power source can be substituted.
-
Aug 12, 2016 2:07 PMby KidVid,I got lost in some the tech specs but can see how this could be helpful to others in my same boat. From what I could understand it sounds like it could be worth investing in an Apple Mini DisplayPort to Dual-Link DVI. Even though all my monitors are only 1920 x 1080 @ 60 Hz, it couldn’t hurt to pick up a little extra power through the USB pigtail. What do you think?
My Monitors only offer DVI and HDMI, I unfortuanly don’t have any [Full-size] DisplayPort or Mini DisplayPorts on my monitors. On my monitors I am using the DVI ports and using active DVI cables. Is this ok?
Special thanks to Grant Bennet-Alder!!!!
-
Aug 12, 2016 3:34 PMby Grant Bennet-Alder,it could be worth investing in an Apple Mini DisplayPort to Dual-Link DVI
I think that is a waste of money unless you need Dual-Link DVI to run a wide display (and in that case you should use the built-in Dual-Link DVI port before converting.) Dual-Link DVI doubles the number of color signals by adding three more pairs of wires with additional color information. It is not needed and not used unless you have a Dual-Link DVI display. And the adapter costs US$100.
It might be worthwhile in the future to only purchase Dual-Link DVI cables, as these are only a few dollars more and can be used for both narrower and wider displays.
On my monitors I am using the DVI ports and using active DVI cables.
You and I do not appear to be using the same terminology. As far as I know, the cables for these displays have wires only, and in my parlance, wires cannot possibly be ACTIVE.
When I say ACTIVE, powered adapter I mean a US$40 adapter from Mini DisplayPort that was sold as ACTIVE, that converts Mini DisplayPort to DVI or HDMI. It generally uses the modest power pin in the Mini DisplayPort interface to get its power. Respected adapters are made by Accell and StarTech, among others (but these guys also make adapters that are NOT ACTIVE.)
-
Aug 13, 2016 12:43 AMby KidVid,Thank you again Grant for your patience and guidance.
For better or for worse I am currently running mostly active adapters. (Two are Accell)
This has become a frustrating case that I wish I could just throw some money at to make work again like it used to.
I had hoped that the card could use a lil extra power boost from the expensive Duel-Link DVI (usb pigtail).
I have read somewhere that when the OS 10.9.3 upgrade came out, many “third monitors” stopped working. I however believe I was still able to run all 6 monitors through out that time. Again, they just would randomly stop powering their third monitor at times and other times they would be fine.
Remember this same issue happened on the other MacPro I often use that is currently running 10.7.5.
At this point I think I will order all new (9) ACTIVE Mini DisplayPort to HDMI adapters and might. I think it could be worth just investing in one Apple Mini DisplayPort to Dual-Link DVI for trouble shooting and as a last resort.
What do you think?
-
Aug 13, 2016 7:27 AMby Grant Bennet-Alder,Debug two displays at a time and make sure all are working that way, then add the third display, making sure that at least one of the three adapters is ACTIVE.
If a setup does not work, try substituting known-good components and check for bad adapters or bad cables (where the problem follows the adapter or cable).
The expensive Apple Dual-Link cable does not boost the power to anything but itself, but it is an industrial solution that should work first time, every time.
-
Aug 16, 2016 2:05 PMby KidVid,Update:
All the testing I was doing that lead to trying to get some help here could be described as:
"Monitor A & B work. C doesn't. I switch some adaptors. Then A & C works and B doesn't."
At this point I'm desperate to get on the Ebay and order some new adapters and cables. Its my fault as I have had a tendency to confuse my language when referring to cables and adapters. My plan is to buy one expensive Apple Duel-Link ADAPTER" along with some new "active" ADAPTERS (Accell and StarTech) and even a few extra CABLES "Dual Link DVI CABLES" to throw into the mix and do some more trouble shooting.
Does this sound like a good investment considering my quagmire?
Next time I crawl underneath there and do some trouble shooting I think i will turn the computer off then plug in a combination of CABLES and ADAPTERS then turn the computer on instead of switching adapters and cables on the fly and letting the screen automatically refresh themselves with each try. I have read somewhere that you have to "Clear Catches" every time you experiment.
This will add a lot more time and strain to my troubleshooting/ experiment process. Is turning off and on, off and on really necessary?
-
Aug 16, 2016 2:48 PMby Grant Bennet-Alder,"Monitor A & B work. C doesn't. I switch some adaptors. Then A & C works and B doesn't."
That matches perfectly with what is expected to happen without a properly-working ACTIVE adapter in the mix. More than three otherwise-working "legacy" displays attached, and the third one on the card conks out.
As I tried to say before, you do not need the expensive Apple adapter. Save your money for a reward for yourself when you get this all sorted out.
For these experiments, there is nothing to be gained from clearing caches, as this has nothing to do with caches. Display cables have alway had very low signal levels, and are quite safe to plug and unplug without powering off anything. The Mac senses when the Mac-end of a cable is plugged in, so make that connection LAST for best results. No need to do a Restart each time.
