Weird duplicate + combined resolution + display on both monitors despite one monitor not being detected glitch!

Understanding and Resolving Display Duplication and Resolution Issues on Dual Monitors

In the realm of multi-monitor setups, encountering display anomalies such as duplication, incorrect resolution scaling, and detection issues can be perplexing. Recently, a user reported a peculiar behavior where their dual monitor configuration, which previously functioned flawlessly, suddenly exhibited the following problems:

• The primary monitor (2560×1440 at 165Hz) and a secondary monitor (2560×1440 at 170Hz) both display identical content, regardless of user settings.
• Windows only detects one monitor, yet the display appears on both screens.
• A new combined resolution option (5120×2880) is available, which spans across both monitors, but it results in a stretched, incorrect display aspect ratio.
• Standard troubleshooting steps such as disabling/enabling displays have proven ineffective.

Understanding the Problem

This issue involves several interconnected factors:

1. Display Detection Discrepancy: Windows reports only one monitor detected, even though the display output appears on both screens.
2. Duplicate Display Output: The content is mirrored rather than extended, which is unintended behavior in many use cases.
3. Combined Resolution Option: The presence of a combined resolution (5120×2880) indicates that the system perceives the two monitors as a single large display, often associated with extended or mirrored modes.
4. Resolution Scaling Issues: Choosing the combined resolution stretches the display across both monitors, distorting the aspect ratio, while selecting native resolutions results in duplication.

Potential Causes

• Graphics Driver Malfunction: Outdated or corrupted drivers can cause detection and display issues.
• Display Settings Misconfiguration: Incorrect settings in Windows or graphics control panel.
• Hardware Connection Problems: Loose or faulty cables, or incompatible adapters.
• Display Adapter Limitations: Some GPU or driver configurations may misinterpret multi-monitor arrangements.

Recommended Troubleshooting Steps

1. Update Graphics Drivers:
2. Download the latest Radeon GPU driver directly from AMD’s official website.

3. Use AMD’s Radeon Software to perform a clean install:

   • Uninstall current drivers via Device Manager or AMD Cleanup Utility.
   • Restart your system.
   • Install the latest driver package.

4. Check Display Configuration Settings:

5. Right-click on the desktop and select Display Settings.
6. Verify if multiple monitors are recognized:
   • If only one is detected, click Detect.
   • Ensure