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macOS Reduced Ethernet Performance with Select DisplayLink Based Products

Last Update: August 10th, 2023
Article ID: 948146

Updated 2021-06-02

Problem Description:

Plugable USB 3.0 and USB-C docking stations with DisplayLink DL-3900 network adapters may have sub-Gigabit Ethernet performance when used with Apple computers. This only affects the wired Ethernet connection on the docking station or graphics adapters with Ethernet during large file transfers or speed tests on upstream connections that exceed 300Mbps. It does not affect the 4K DL-6950 based docking stations or graphics adapters with Ethernet.

Network performance may be limited to 250-300Mbps download and between 500-700Mbps upload when using these products, internet speed tests and file downloads may be further limited based on some customer feedback we have received.

While this issue is under investigation, it is unclear if drivers will be released to improve Mac network performance. Customers that require maximum network throughput may wish to utilize WiFi or another USB Ethernet adapter based on a different chipset. For example our USB3-E1000 USB 3.0 Gigabit Ethernet Adapter can be connected to one of the docking station's USB 3.0 ports to provide improved network performance. This network adapter requires installing separate drivers with detailed installation instructions available here: https://kb.plugable.com/question/936739

Affected products:

  • UD-3900 Dual Display Universal Docking Station
  • UD-3900C USB-C and USB 3.0 Dual HDMI USB Docking Station
  • UD-3900C4 USB-C Quad HDMI Docking Station
  • UD-3900H USB 3.0 Dual Monitor Horizontal Docking Station
  • UD-3900Z Dual HDMI USB Universal Docking Station For Windows
  • UD-3900PDH USB-C Triple HDMI Display Horizontal Docking Station
  • UD-3900PDZ USB-C Triple HDMI Display Docking Station
  • UD-ULTCDL USB-C Triple Display Docking Station
  • USB3-3900DHE USB 3.0 Dual Display Adapter for Multiple Monitors with Gigabit Ethernet

Mitigation:

Using a USB 3.0 to Gigabit Ethernet adapter connected to a USB 3.0 port on one of the above docking stations, or a USB-C to Gigabit Ethernet adapter connected to the system directly allows for greater network performance. However we have also found that many USB Ethernet adapters have limited network performance with new M1 based Apple Mac systems.

Both of the above ASIX based USB Ethernet adapters require installing the ASIX network driver for macOS 11, we provide detailed installation instructions in our Plugable Knowledge Base. The Realtek based USB-C to Gigabit Ethernet adapter uses macOS built-in USB network drivers.