Latitude 5440 Thunderbolt 4 Ports - Only One Supports Display Output After Motherboard Replacement

Device: Dell Latitude 5440 (13th Gen Intel)
OS: Windows 10 22H2 (Build 19045.5371)
GPU: Intel Iris Xe (Driver v32.0.101.6078)
External Monitors: 2 × Dell S2722QC (USB-C DP 1.4 mode, 4K, 65W power delivery)
Power Supply: Dell S2722QC (65W USB-C PD) & Ugreen CD216 65W USB-C charger

Issue:

I have a Latitude 5440 with two Thunderbolt 4 (TB4) ports on the left side. According to Dell’s official specifications, both ports should support DisplayPort Alt Mode and two 4K displays. However, after a motherboard replacement, I ran into a frustrating issue:

Before the motherboard replacement:

Port A (right TB4 port): Fully functional (video output, charging, data transfer).

Port B (left TB4 port): Could charge and transfer data but did not output video.

After the motherboard replacement:

Port A no longer outputs video, only charging and data transfer.

Port B is now fully functional.

Effectively, the issue has swapped ports—Port A was working before, but now only Port B works for video.

What Dell Support Said:

I contacted Dell support, and they sent a technician to replace my motherboard. However, after the replacement, the issue persisted—just on the opposite port.

- The technician called Dell HQ for advice but was unable to resolve the issue.

- Dell's explanation was that "running dual 4K monitors via two TB4 ports may put too much strain on the system".

- They suggested using HDMI + TB4, which works but is not what I want.

- They also suggested purchasing a Dell docking station—but my understanding is that Latitude 5440 should natively support dual 4K monitors via TB4.

Key Concerns:

1. Should both Thunderbolt 4 ports on the Latitude 5440 be able to output video?

2. Is this a BIOS/firmware issue, or a hardware limitation?

3. Is it expected behavior for one TB4 port to function as a full TB4 while the other defaults to USB 3.0 data only?

4. Could this be caused by a faulty replacement motherboard? My replacement board was refurbished, and I’m wondering if I should push for another replacement.

Additional Notes:

- Dual 4K displays work fine when using HDMI + TB4, both running at 4K 60Hz.

- If both TB4 ports cannot support dual monitors simultaneously, I would at least expect the laptop to allow me to choose which port to use for video output. Right now, it's locking me into one specific TB4 port for video, while the other is completely disabled—which seems like a limitation rather than expected behavior.

Would appreciate any insights—has anyone else experienced this issue with the Latitude 5440 or similar Dell laptops? Thanks in advance!