MP 1,1-5,1 no Dual Disaply

[Bobbych]

I have been setting up my 5,1 on a single monitor to just to get it working. Now I want to switch it to my main desk setup which has 2 monitors

my Machine is a 5,1 which as a FLASHED AMD Radeon 5790 3GB GPU, running Big Sur

the Card has 2xDVI outputs, 1 x HDMI, 2x mDP

now, if I plug in a single monitor into any of the DVI, or HDMI, it works.

if I try to plug in a second monitor to any of the DVI or HDMI, there is no output, and it is not recognised in Mac OS. I have not tested the mDP as I have no cables for those

How can I get dual monitors to work?

 

[MarkC426]

Do you mean a 7950..?
Dual monitors (or more) are just plug and play.

Either a dodgy screen/cable/gpu.

 

[Bobbych]

Yes 7950

I have plugged in each monitor on its own, and they work, on both hdmi and DVI so the ports and cable work. But I cannot get two screens to show at the same time. When I connect the cable the screen knows it is connected but says no signal is being received

 

[MarkC426]

This could be an 'open core' related issue.

 

[Bobbych]

I will install high Sierra on a spare drive and try that so that will eliminate OC