radeon 7970 3 displays

Question

Level 1

4 points

radeon 7970 3 displays

Maybe someone can help me with this issue. I have a Radeon 7970 mac edition in my cMP 4.1->5.1 with 2x x5690, 48g RAM triple channel. I have a 3 Monitors connected, one via the DVI port, 2 with active MDP Adaptors on the MD ports. When I boot up only the DVI connected Monitor comes up, both others stay black. When i unplug and replug them, all three monitors behave as they should in maximum resolution.

When I connect one of the smaller monitors to the HDMI port and one the MD port, on boot up the DVI and the HDMI monitor come on, the MD port Monitor stays black. After replugging MDP Monitor, Monitor is working. When rebooting (without shutdown) all Monitors work as they should. PRAM and SMC reset done. Any ideas?Thanks in advance

OS X Yosemite (10.10.5)

Posted on Jan 14, 2017 7:59 AM

Reply

Answer 1

Narcotixx Author

Level 1

4 points

Jan 15, 2017 12:18 PM in response to Grant Bennet-Alder

The main Display is 32 inch Samsung S32D850T Monitor on the Dual link DVI out with a dual link cable, resolution 2560x1440. secondary and tertiary Monitors are Samsung Syncmaster BX2431 on 1920x1080, connected on either both MDP or one on the HDMI port and one on the MDP. Adapters are Startech active MDP to HDMI adapters (BX2431 only have HDMI inputs). No configuration work after booting, using the HDMI port and one MDP on the 7970 or using both MDP on the 7970. By reconnecting both BX2431 on either configuration, all monitors work, even if I use only one active adapter on dual MDP configuration. Seems weird to me. Only explanation for me remains that the 2nd and 3rd Monitor have to use DVI as well, wich they can´t as they have only HDMI Inputs. Help appreciated.

Reply

Answer 2

Jan 15, 2017 1:11 PM in response to Narcotixx

A stunt cable is one that has a different type of connector on the different ends, and effects a simple adaptation, not as serious as a conversion, but more complex than a sex-change. No active components, just a re-wire. It just has one small "trick" or "stunt" built into it.

[Mini] DisplayPort to [Full Size] DisplayPort cable is the clearest example of a stunt cable by that definition.

Reply

Answer 3

Jan 15, 2017 7:49 AM in response to Narcotixx

Exactly what adapters are in use, and what inputs on what displays at what resolutions?

Reply

Answer 4

Jan 15, 2017 12:35 PM in response to Narcotixx

Single-Link DVI adapts to 1920 by 1080p HDMI with only a re-wire (such as a stunt cable). The signals used and the signal levels are completely compatible.

Reply

Answer 5

Narcotixx Author

Level 1

4 points

Jan 15, 2017 12:38 PM in response to Grant Bennet-Alder

Thx for the quick reply, but what is a stunt cable?

Reply