Added 3rd monitor and now it's an "either/or" situation 2DVI 1VGA


I added a third monitor and now it’s either the new single monitor with VGA at the correct resolution and two mirrored monitors or the other two with DVI as right and left and the central VGA monitor at some extremely low resolution. I bought a new 27" widescreen as my primary display from the VGA out on the closed laptop. When I set a resolution of 1920x1080 on the center monitor, the two others revert to the “mirror” setting. When I set each mirror setting, one left and one right, the right and left monitors reset the center monitor to an inferior resolution. It’s an either / or situation that I can’t seem to remedy.!](](


Thanks for posting and the great diagram to show your setup! We’ll be able to help. First, a quick question: are you on XP, Vista, or Windows 7?


Windows Vista 32bit


Thanks, that helps.

One thing to note is that Windows 7 has improved multiple monitor support (see!5526025/make-… for a good article on it), and it’s also faster and consumes less resources than Vista (which is rare, usually OS upgrades are more hardware hungry!). So if you’re investing a lot in a setup, it may be worth the pain of an upgrade.

That said, let’s see if we can do better here. First off, if you set all three monitors to extend the desktop, are you able to make use of the full resolution of all three monitors?

If so, can you run all extended, or do you have particular goals in mind where you want to mirror - what are they? Mirroring has the consequence that Windows must always make the two monitors have exactly the same mode – which means it must choose a lesser mode to match the lesser monitor.

Hope we’re getting closer. Thanks again!


Hi Bernie,

Let me start by saying that I have had multiple monitors for over 10 years. I am an electronic musician and a graphic artist. My studio PC is down while I build a far superior PC utilizing 4 to 6 cores. I wanted to emulate my past desktop from a laptop until my new PC is ready.

I have no interest in mirrored mode. I want the center monitor to hold the 1920x1080 native resolution for that monitor while the plugable devices create a left and right monitor at the native resolutions of the Princeton Synergy 981’s [1280x1024]

That’s it…

But I’m thinking that the video card in the laptop must be too weak to create an analog 1920x1080 at the vga output and 2 digital 1280x1024 USB outputs to feed the plugable devices, or however that works???

I have already tried to do 2 analog 1280x1024 usb outputs, but that failed in many many ways, which is why I was very happy when the digital usb outputs worked great. Things got crazy when I added the new LED center monitor and ran a straight vga cable from the only direct output on the laptop to the 27" monitor.



Some links you might need…
Princeton Senergy 981:,2817,…


Acer 4730Z:…

And thank you for the interesting article about multiple monitors on life-hacker.


When the new PC is complete, I’m going to use the Asus 27" as the main monitor from a DVI or HDMI output from a powerful video card. I’ll probably have enough processing power on the video card to not be forced to use the plugable devices to extend the monitors, but It sure would be nice if I could get the system working the way I have described until I do the change over.


ozone333 Electronic music


Thanks for all the great further info! Let’s see if we can make more of the older setup, until the new arrives.

A quick question: What resolution does the center (VGA-attached) monitor have to go down to, before you can have all 3 monitors in extended mode?



I fixed the issue as I was cycling through the available resolutions…

There was this incessantly annoying dialog box that kept popping up at the bottom of the screen that said something like… “1920 x 1080 is the correct resolution for this monitor. Click here to set this monitor at the correct resolution”

Each time in the past, I would click that windows dialog and the whole monitor thing would reset with the center monitor on 1920 x 1080 while the 2 plugable connected monitors would be back at the Mirror mode and back on 1280 x 1024.

This time, I ignored the pop-up dialog because I was busy trying each frequency above 1280 x 800 which was the highest setting I could use from the windows Display Settings panel. Each subsequent resolution was created by the Intel Graphics Media Accelerator driver for Mobile. I slowly incremented each center monitor setting, up by one set until I got to 1920 x 1080 without ever clicking on that evil dialog.

I am using the three monitors right now. I would have never known that this was possible if I hadn’t cycled through monitor resolutions one by one because that evil dialog prompts you to correct the problem through windows which most of us trust as being the right thing to do.

I’m glad the extended monitors are working now! !]( maxed out Windows Display settings panel](


Thanks for sticking with it to get in a good state! Great job!


I’m having a new problem now though… the right monitor, [plugable connected] keeps randomly having a screen issue where the screen goes blank for 1/2 a second then comes back. It’s not the monitor turning off, I checked, it’s some type of erratic behavior with that monitor only. it’s very annoying.


Could you open Windows’ Device Manager and see if the adapter is disappearing/appearing from there at the same time the screen blanks (thus it’s disappearing at the USB level)? If that’s the case, you should also be hearing Windows’ system sounds for device arrival/removal (bing-bong type sound).

Let us know. Depending on whether the problem is at the USB level, we’ll be able to figure out next steps.