DisplayPort over USB Type-C Adapters Not Supported on OptiPlex and Dell Precision Desktop and Rack Workstations with Specific Add-in Cards

Summary: DisplayPort (DP) over USB Type-C adapters not supported with OptiPlex desktops or Precision Workstations using Sunix USB 3.1 Type-C Add-in card or Dell Precision Thunderbolt 3 Add-in Card. ...

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Symptoms

Display over USB Type-C adapters not supported with specific add-in cards

Various display issues (flicker, lost video after power cycle/S3 cycle, not able to detect) may occur on multiple OptiPlex and Dell Precision desktop and rack models if you attempt to connect a display to the Sunix USB 3.1 Type-C Add-in card or Dell Precision Thunderbolt 3 Add-in Card.

Cause

The computer topology when a Sunix Add-in card or Thunderbolt 3 is installed complicates the computer design. Less than favorable graphic signal strength results when a display is connected to the Sunix USB 3.1 Type-C Add-in card or Dell Precision Thunderbolt 3 Add-in Card.

Unlike mobile computers and computers with USB Type-C ports integrated into the motherboard, computers with an Add-in card DP loop back Type-C port do not receive DisplayPort signals directly from the graphics chipset. The result is degraded signal strength and poor graphics performance when you connect a display using a USB Type-C to DisplayPort adapter to the Add-in card port.

Resolution

Use the existing DisplayPort or mini-DisplayPort connections of the computer graphics adapter for video display.

Note:
  • USB Type-C and Thunderbolt 3 data operations do not have this limitation.
  • Native Type-C displays do not have this limitation.

Affected Products

Alienware, OptiPlex, XPS, Fixed Workstations, Dell Canvas 27
Article Properties
Article Number: 000125432
Article Type: Solution
Last Modified: 07 May 2026
Version:  13
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