Monitor Refresh Rate Decreases After Rebooting When Thunderbolt Daisy Chain is set to Optimized

Summary: This article discusses the Dell U3425WE monitor refresh rate decreases after rebooting, when the Thunderbolt Daisy Chain setting is set to optimized.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms

Affected Products:

  • Dell U3425WE Monitor
  • Dell Thunderbolt Dock - WD22TB4

Cause

The ALT mode not being changed is the cause of this issue.

Standard: If the first monitor claims HBR3 4 lane, the second monitor is HBR3 1 lane, HBR2 2 lane, or HBR 4 lane.

Note: HBR3 4 lane can support 3440 x 1440 @120Hz 10bit.

Optimized: If the first monitor claims HBR2 4 lane, the second monitor is HBR2 4 lane. If both first and second monitors are set as Optimized (HBR2 4 lane), this issue can be avoided.

Note: HBR2 4 lane can support 3440 x 1440 @120Hz 8bit.

U3425WE OSD Thunderbolt Daisy Chain set to Optimized

Resolution

Workaround:

A user can recover from this situation by doing one of the following:

  • Unplug and then re-plugging the Thunderbolt 4 cable between the laptop and first monitor.
  • Unplug AC cable and re-plug in cable to first monitor.
  • Turn the first monitor off and back on.

Solution:

  • Set both monitors Thunderbolt Daisy Chain Setting to Optimized.
    • If the first monitor setting is Optimized and the resolution is set to 3440 x 1440 @60Hz.
    • The second monitor is set to Standard.
    • Try changing the setting again (Optimized > Standard > Optimized).

Affected Products

Dell U3425WE, Dell Thunderbolt Dock – WD22TB4
Article Properties
Article Number: 000223924
Article Type: Solution
Last Modified: 18 Apr 2025
Version:  5
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