Thunderbolt 4 daisy-chaining fails on the Dell U2722DE because its upstream port is USB-C 3.2 Gen 2, not Thunderbolt. This monitor cannot pass a Thunderbolt signal to downstream devices. You must use DisplayPort 1.4 MST for multi-monitor setups or connect peripherals directly to your host computer.
Understanding the Hardware Limitation
The core confusion stems from mixing up connectivity standards. The Dell U2722DE features a single upstream connection that uses a
USB-C 3.2 Gen 2 interface. While this port supports high-speed data transfer and video output, it does not implement the Thunderbolt protocol. Thunderbolt 4 requires specific hardware controllers and cabling that are physically similar to USB-C but electrically distinct. Because the monitor lacks a Thunderbolt controller, it acts as a passive bridge rather than an active Thunderbolt hub. Consequently, any device connected to the downstream ports of this monitor will not see a Thunderbolt bus. If you attempt to chain a Thunderbolt SSD or another Thunderbolt-enabled dock behind this monitor, the connection will fail to enumerate properly, often resulting in the device not appearing in your system’s device manager or disk utility.
This limitation is critical for users building complex workstations. Many professionals assume that because the connector looks like a USB-C port, it behaves like one found on a Thunderbolt-equipped MacBook Pro or Windows laptop. However, the Dell U2722DE is designed primarily as a display with basic peripheral passthrough via USB-A and limited USB-C data lanes. It does not support the bandwidth aggregation or low-latency signaling required for true Thunderbolt chaining. Attempting to force this configuration will lead to instability, dropped connections, or complete failure of the downstream devices. For those needing robust daisy-chaining capabilities, alternative monitors with native Thunderbolt 3 or 4 support are necessary. See our guide on
Thunderbolt 4 Daisy-Chaining Not Working Correctly on Dell U2722DE USB-C 3.2 Gen 2 Upstream Port for more detailed diagnostics on why this specific hardware setup causes such headaches.
Configuring Multi-Monitor Setups with DP MST
Since Thunderbolt chaining is impossible, the correct method for using two screens involves DisplayPort Multi-Stream Transport (MST). The Dell U2722DE supports DisplayPort 1.4, which allows for MST hubs. To set this up, you need a dedicated MST hub or a monitor that supports MST input. Connect your primary source computer to the first monitor using a DisplayPort cable. Then, use a DisplayPort cable to connect the first monitor’s "Out" or "Daisy Chain" port to the second monitor. Ensure both monitors are set to accept DisplayPort signals rather than USB-C video inputs.
In your operating system’s display settings, you should now see both monitors as separate displays. Windows and macOS handle MST differently; macOS has historically had limited support for non-Apple MST hubs, so verify compatibility if you are using a Mac. If the second screen remains black, check the physical connections. DisplayPort cables must be securely seated, and the MST feature must be enabled in the OSD (On-Screen Display) menu of the monitors involved. Some older or cheaper MST hubs may not support the resolution or refresh rate you are attempting to drive. Stick to VESA DisplayPort 1.2 or higher certified cables to ensure stability.
For users experiencing broader connectivity issues where ports report incorrect speeds, it is worth investigating general USB version mismatches. Sometimes, what appears to be a daisy-chaining failure is actually a negotiation error between the host and the hub. Learn more about resolving these speed discrepancies in our article on
USB A 3.2 Gen 2 and USB C 3.2 Gen 2 Ports Showing 2.0.
Alternative Peripheral Connections
If you need to connect peripherals like keyboards, mice, or webcams, do not rely on the monitor’s downstream ports for high-bandwidth devices. The USB-C upstream port on the U2722DE provides limited data lanes. Most of the USB traffic goes through the monitor’s internal hub, which shares bandwidth with the video stream. For optimal performance, connect high-priority peripherals directly to your host computer’s available ports. This reduces latency and prevents bandwidth bottlenecks that can cause stuttering in video playback or input lag in gaming.
If you require multiple USB ports and the monitor’s hub is insufficient, consider using a powered USB-C hub connected directly to your computer. Avoid using unpowered hubs for devices that draw significant power, such as external hard drives. Always prioritize direct connections for storage devices to ensure data integrity and speed.
Frequently Asked Questions
Can I use a Thunderbolt cable with the Dell U2722DE?
Yes, you can physically plug a Thunderbolt cable into the USB-C port, but it will not function as a Thunderbolt connection. The monitor will treat it as a standard USB-C or DisplayPort connection depending on how it is negotiated. You will not gain any Thunderbolt benefits like daisy-chaining or increased bandwidth.
Why is my second monitor not detected when chained?
Your second monitor likely requires a DisplayPort MST hub or a compatible monitor with DP-in support. The Dell U2722DE cannot pass a Thunderbolt signal, so chaining via USB-C is impossible. Use DisplayPort cables and ensure MST is enabled in the monitor settings.
Does the U2722DE support USB-C video input from a MacBook?
Yes, the upstream USB-C port can carry video from a MacBook if the MacBook supports DisplayPort Alternate Mode over USB-C. However, this only works for a single display connection to the monitor itself, not for chaining additional devices behind it.
What is the maximum data speed of the upstream port?
The upstream port operates at USB 3.2 Gen 2 speeds, which translates to 10 Gbps. This is sufficient for fast external SSDs but significantly slower than Thunderbolt 3 or 4, which offer 40 Gbps.
Can I replace the USB-C port if it breaks?
Replacing the USB-C port on the Dell U2722DE is a complex soldering repair that requires specialized equipment. It is generally recommended to use a different upstream connection method or replace the monitor if the port is damaged, rather than attempting a DIY fix. Check guides on
Replacing USB-C Hub Plug: A Guide to Troubleshooting and Solutions for general concepts, though board-level repair is advised for this model.