I'm not sure where to ask this question. I have a dual monitor setup with a new MB (ASRock Z77 Extreme6), and I am using the built-in graphics controller for my video. I have two monitors, both with DVI connectors. I have connected from the motherboard DVI and also the HDMI ports (using an HDMI-DVI cable for the latter). My desktop is set up as landscape orientation and the Multiple Display option is set to "Extend these displays" However, to do some troubleshooting with a monitor occasionally blanking out, I switched the cables: I would have expected the display to switch also. Much to my surprise, the display did not switch. In other words, Monitor 1 continued to show the left side of my Windows desktop; and Monitor 2 continued to show the right side. Can someone explain to me what is going on? Thanks. -- RonRon

Hello Ron I have found that the position of the video output will have an impact on the number the monitor is assigned. For simplicity, a standard dual head video card with a DVI-D port on the left and a VGA port on the right will assign the first output ( in this case the DVI-D port) to number 1 and the second output (vga) number two. Take it a little further and connect two addon video cards both with dual head outputs (DVI-D and VGA). Windows assigns the first addon cards DVD-D number 1, the second addon cards DVI-D now becomes number 2. Now the first addon cards VGA is assigned to number 3 and the second addon card vga is now assigned number 4. The easiest solution to this is to go back into the screen resolution, and left-click/hold to drag the monitor to the correct location. you can also move the monitors up and down to mimic the position of how your monitors may be setup. Hope that helps

Michael, Thanks for your response. But when I switched the cables, the screen (extended across the two monitors) did NOT change, and the monitor in the left hand position (my left) continued to display the left half of the extended windows desktop; and the monitor on the right continued to display the right half of the extended windows desktop. I don't require a "solution" as there does not seem to be a problem. What I would like is an explanation as to why switching the cables did not result in the left half of the extended windows desktop displaying on my right hand monitor (and vice versa). One possibility is that the act of switching somehow "reset" the detection to the baseline. (I did have to switch one and two when I first set this up in the original configuration). But the two monitors are the same, so I'm not sure how/why that would have occurred. I suppose I could go switch things back and forth, and see if the #1 and #2 assignments switch, but that'll be a task for another day, after my troubleshooting of the intermittent screen blanking is done. Ron

Hi, Windows system only detects the terminal hardwares-two monitors, it ignores the cable or ports. So when connecting, system will decide the display location based on the settings under Screen Resolution, not the location of the cables or ports. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hmmm. But what I did when I switched cables was to attach the computer that had previously been attached to the DVI adapter, to the HDMI adapter, and vice versa. But the screen layout did not switch with that. (See diagram above). In other words, the output that had been going down the DVI-DVI cable, was now going down the HDMI-DVI cable; and vice versa. Ron

Hi, Please check if the "Display" name on Monitor 1 is changing after you switch the cables for Monitor 1. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thank you Ruby, Windows is clearly behaving like that. Do you know how it does that though? The two monitors appear to be identical, but I guess there must be some difference in one of the properties that identifies the individual monitor.Ron

I'm not at that location now (and won't be for a few weeks), but the Display names of the two monitors were identical after the switch. By that I mean, the monitor 1 name was the same as the monitor 2 name. I can think of two possible explanations, but both depend on the system (motherboard or OS), somehow being able to tell the difference between the two monitors, even though they appear to be identical. I'll have to go through the properties in some detail when I get back there.Ron

Hi, The two monitors' names may be the same, but the locations may be different. We can check the location information as below: Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hi, Yes, we can also click Advanced settings under Screen Resolution to check more details such as the Resources and Details. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.