I have two ATI Radeon 5450 graphics cards in my PC (driving 4 monitors). On the first card, monitors 1 and 2 are identified as monitor 1 (even though they're both using separate cables/connections). Monitors 3 and 4 (on card 2) are identified as monitors 2 & 3.
I've never seen this behavior before! When I click on "Identify" int the AMD Catalyst Control Center app, the two monitors connected to card 1 are identified as monitor 1 (i.e. the computer thinks I have 3 physical monitors, not 4).
How do I correct this issue? Is there a jumper on the card that has to be set?
The OS is Windows 10 but this problem occurs WAY before Windows is involved. When I turn the machine on they are seen as a single monitor. This is a new system. Built from the ground up.
Note, too, that these two monitors are dimmer, slightly, than the pair that sits next to them on the other Radeon card.
The configuration for the connectors are done by your cards maker. I would ask this question to the company that made your card.
Plus whoever you talk to, let them know what OS and driver you are using so they can help.
If you think AMD can help you can contact them here: Support Ticket Process | AMD