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In a triple monitor setup only 2 display can be duplicated

Jobineu 0 Reputation points
2025-10-12T05:57:44.3733333+00:00

Hello, I have a PC with 2 monitors and the living room smart TV is also connected with an HDMI cable as a 3rd monitor. I was easily able to both extend or duplicate all 3 of them so when it is extended they were acting as 3 monitor and if I pressed duplicate all 3 of them showing the same thing. Yesterday I changed the 2nd monitor of my PC to a newer one and since the change the 3 monitor extension still works, however I can't duplicate the same screen to all 3 displays, only 2. I have no clue what is the issue, the new monitor uses the same display port cable the previous one had. In the display settings it only lets me connect either the 2nd monitor or only the TV to the main monitor but never all 3 at the same time. It worked just fine before the monitor change. And when choosing only 2 monitor the new monitor can be dual shared with the main one so it works, just not all 3 at the same time. Does anyone know what triggered the options change after switching up a monitor?

Windows for home | Other | Devices and drivers
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  1. Jason Roberts 2,105 Reputation points Independent Advisor
    2025-10-12T11:26:32.0933333+00:00

    Hi Jobineu,

    My name is Jason and I am an independent advisor and windows user like yourself.

    This is a classic case of EDID mismatch or GPU output limitation triggered by the new monitor’s specs. When you swapped the second monitor, Windows and your GPU re-evaluated what duplication is possible based on resolution, refresh rate, and signal compatibility across all three displays.

    Why Triple Duplication Broke After Monitor Swap

    • Duplication requires identical signal compatibility across all displays
    • Your new monitor likely has a different native resolution or refresh rate
    • Windows can only duplicate to displays that match or accept downscaled signals
    • The GPU may now see the new monitor as incompatible for triple mirror mode

    Fixes to Restore Triple Duplication

    1. Match Resolution and Refresh Rate Across All Displays

    • Go to Display Settings → Advanced Display Settings
    • Set all three displays to the same resolution (e.g., 1920x1080)
    • Set all to the same refresh rate (e.g., 60Hz)

    This forces Windows to treat them as compatible for duplication.

    2. Use NVIDIA Control Panel to Force Clone Mode

    • Open NVIDIA Control Panel
    • Go to Set up multiple displays
    • Right-click your main display → Choose Clone with → Select both other displays
    • If it fails, try cloning one at a time, then add the third

    NVIDIA sometimes allows more flexible cloning than Windows Display Settings.

    3. Try DisplayPort MST or HDMI Splitter (Hardware Solution)

    If software duplication fails:

    • Use a DisplayPort MST hub or HDMI splitter to send the same signal to multiple screens
    • This bypasses Windows limitations and mirrors hardware-level output

    Ideal if you need true triple mirror mode for presentations or signage.

    4. Check GPU Output Limits

    • Some GPUs (especially older or mobile ones) limit duplication to 2 displays
    • Check your GPU specs for maximum simultaneous clones
    • If you're using integrated + discrete GPU, ensure Hybrid Mode is off and NVIDIA is primary

    Let me know your exact GPU model and the resolution/refresh rate of each display — I can help you script a matching setup or recommend a hardware clone solution if needed. You're close — and this is fixable with a bit of signal wrangling.

    1 person found this answer helpful.

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