I am trying to run 3 monitors on my ATI Sapphire HD 5770

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Level 1

17 points

I am trying to run 3 monitors on my ATI Sapphire HD 5770

I have a computer that for years worked with multiple monitors fine… until now. I don’t know what I am doing differently. Please help me.

Mac pro with (6) monitors via (2) 5770 cards.

Top card continues to drive 3 monitors fine but now the bottom card only powers two.

Each card has one DVI and 2 mini ports.

I am using all active cables and all active adaptors.

I have just bought some extra passive, powered and lots of extra active adaptors to experiment and trouble shoot with.

Thank in advance for help and time 🙂

Mac Pro, OS X Yosemite (10.10), 3.46GHz (5,1) 6 core (48G RAM 1333)

Posted on May 27, 2015 4:52 PM

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Answer 1

BDAqua

Level 10

238,973 points

May 27, 2015 5:20 PM in response to KidVid

If you remove a couple of monitors from the one that works, does the other card then work after a reboot?

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Answer 2

KidVid Author

Level 1

17 points

May 27, 2015 5:28 PM in response to BDAqua

No, as i trouble shoot and play with adaptors on the suspect card, the monitors end up swithing.

An example: Monitor A & B work. C doesn't. I switch some adaptors. Then A & C works and B doesn't.

Also while testing, i dont have to re-boot.

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Answer 3

KidVid Author

Level 1

17 points

May 27, 2015 7:54 PM in response to KidVid

In other words, does anybody know what is necessary to get all 3 monitors to work?

All active adaptors?

At least one powered active adaptor?

At least one passive adaptor?

Any particular type of DVI cables?

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Answer 4

BDAqua

Level 10

238,973 points

May 27, 2015 10:20 PM in response to KidVid

Also while testing, i dont have to re-boot.

I'm not sure of that, it may even require a Safe Bootto help clear caches. 🙂

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Answer 5

KidVid Author

Level 1

17 points

May 28, 2015 2:45 AM in response to KidVid

Does anybody know what is necessary to get all 3 monitors to work?

All active adaptors?

At least one powered active adaptor?

At least one passive adaptor?

Any particular type of DVI cables?

As I trouble shoot I am able to get live realtime results without rebooting. This makes the testing process easier but its still frustrating.

Please help.

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Answer 6

KidVid Author

Level 1

17 points

May 28, 2015 7:53 PM in response to KidVid

Bump

Please help me.

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Answer 7

May 28, 2015 8:41 PM in response to KidVid

The documentation says you get two "legacy" displays free (where "legacy" means anything that is not DisplayPort family) and the next one(s) require ACTIVE adapters.

Either you do not have enough ACTIVE adapters, or you have some dysfunctional hardware.

If you want help, Readers need exact details of what you are connecting with exactly what adapter to exactly which port.

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Answer 8

May 28, 2015 8:47 PM in response to BDAqua

The Mac sends a new query to your display (which it MUST answer on the first try to be usable) and the resolution is re-set when:

• The Mac-end of the cable is inserted.

• At Startup or Wake-from-Sleep.

• when the Option-Detect_Displays button is used in the Displays Preferences pane.

A display that "hunts" through the display's possible ports, looking for the active port will often miss the Mac's query, and remain dark. If there is an internal setting on the display to force it to the one computer port you intend to use, setting the display that way improves things remarkably.

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Answer 9

KidVid Author

Level 1

17 points

May 28, 2015 9:04 PM in response to Grant Bennet-Alder

Thank you Grant-- I’m unfortunately not ready to eliminate any possibilities yet.

As far as extra hardware:

All my DVI cables are active

I have (8) active adaptors (mini to DVI)

1 extra passive adapter.

1 active passive adapter

The two 5770 cards seem to be OK since they are able to display all the monotors but just not all at the same time. My example above:

Monitor A & B work. C doesn't. I switch some adaptors. Then A & C works and B doesn't.

Fortunately the computer refreshes all the screens every time I continue to juggle adaptors and cables.

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Answer 10

May 28, 2015 9:17 PM in response to KidVid

An ACTIVE Dual-Link DVI adapter [from Mini DisplayPort] only shows a picture when its USB pigtail is getting additional power from a USB port (or a charger or some other source).

RocketFish adapters have disappointed many posters here.

Accel and StarTech adapters seem to work just fine.

Give us a specific example of a setup that does not work, and exactly what devices you are connecting to which ports using which adapters and cables.

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