I have a middle-aged system - Gigabyte GA-X79-UP4 mobo, Win 10 x64, 2x Catleap Q270 monitors @ 2560x1440. For some time I have installed 1x RX480 and 1x HD7800 graphics cards with DVI-D Dual Link connection separately to each monitor - all running fine and well. DVI-D Dual Link is the only connection available on the Catleaps
I thought to get another RX480 to provide a balanced colour rendering (the HD7800 is a little 'creamy'). However, after swapping the HD7800 for an RX480 there was no signal to the 2nd monitor. Two display adapters showed up in Device Manager but not in Radeon settings or Windows Display Settings.
I have tried various combinations of HDMI and DisplayPort to DVI-D Dual Link (incl an expensive Active DP adapter) with no success.
There was even no signal when I tried to run the 2nd monitor off the one RX480 via DP or HDMI - this combo showed up in Radeon settings but not Windows Display Settings.
All Radeon and Windows drivers are up to date as of April 7th 2019
So my conundrum is that the 2-card RX480/HD7800 setup works fine but I cannot get RX490/RX480 to work. Any help or advice would be gratefully received. Thank you