Merge pull request #9117 from v-lianna/CI_6220

AB#6220 Create network-adapters-inaccurate-link-speed.md

Author: Simonx Xu

support/windows-server/shell-experience/network-adapters-inaccurate-link-speed.md

@@ -0,0 +1,46 @@
+---
+title: High-Speed Network Adapters Show Inaccurate Link Speeds
+description: Describes a limitation in Windows user interfaces where the link speed might not be displayed correctly for high-speed network adapters.
+ms.date: 06/17/2025
+manager: dcscontentpm
+audience: itpro
+ms.topic: troubleshooting
+ms.reviewer: kaushika, sheiroqi, v-lianna
+ms.custom:
+- sap:windows desktop and shell experience\file explorer (app only,folders,quick access,file explorer search)
+- pcy:WinComm User Experience
+---
+# High-speed network adapters show inaccurate link speeds
+
+This article describes a limitation in Windows user interfaces where the link speed might not be displayed correctly for high-speed network adapters.
+
+On devices using high-speed network adapters (for example, 400 Gbps or higher), the link speed displayed in Windows user interfaces like Network Connections (**ncpa.cpl**) might be lower than the actual configured speed.
+
+For example, you might observe a displayed speed of 170.5 Gbps even though the hardware is correctly configured for 600 Gbps.
+
+## The link speed exceeds the representable range
+
+This issue is due to a limitation in how certain legacy components query and report link speed information.
+
+Specifically, the Windows user interface retrieves the link speed using a method that returns the result as a 32-bit value, measured in 100-bps units. If the actual link speed exceeds approximately 429.5 Gbps, the value might exceed the representable range and be truncated in the display.
+
+> [!NOTE]
+> This issue doesn't indicate a malfunction of the hardware or system and doesn't affect the actual performance or functionality of the network adapter.
+>
+> The system continues to operate at the correct speed as configured at the hardware level.
+>
+> No action is required unless the display discrepancy causes confusion.
+
+## Verify the accurate link speed
+
+To retrieve the accurate link speed, run the following Windows PowerShell cmdlet:
+
+```powershell
+Get-NetAdapter | Select Name, LinkSpeed
+```
+
+This cmdlet returns the accurate speed as reported by modern networking application programming interfaces (APIs), which support higher-capacity adapters.
+
+## Status
+
+Microsoft is aware of this limitation and is exploring possible improvements in future updates.

support/windows-server/toc.yml

@@ -2506,6 +2506,8 @@ items:
       href: ./shell-experience/default-date-format-changed.md
   - name: File Explorer/Windows Explorer
     items:
+    - name: High-speed network adapters show inaccurate link speeds
+      href: ./shell-experience/network-adapters-inaccurate-link-speed.md
     - name: Increased CPU usage when accessing a FileTable share
       href: ./shell-experience/increased-cpu-usage.md
     - name: TEMP folder with logon session ID is deleted