220-1201 Practice Question: That their new Thunderbolt 4 external GPU (eGPU)…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  The laptop's Thunderbolt 4 port is disabled in BIOS.

  Why it's wrong here

  While a Thunderbolt port can be disabled within the UEFI/BIOS settings, preventing any connected device from being recognized, this is an unlikely cause in this scenario. The fact that the external GPU (eGPU) functions correctly when connected to another laptop strongly suggests that the eGPU itself is operational and that the issue is not a fundamental configuration problem with the host laptop's port being entirely disabled. If the port were disabled, it would typically fail to recognize any Thunderbolt device.

• ✓

  The cable used is a passive USB-C cable, not an active Thunderbolt 4 cable.

  Why this is correct

  Thunderbolt 4 technology, especially for high-bandwidth applications like external GPUs (eGPUs) utilizing PCIe tunneling, necessitates active cables for optimal performance and reliability. Unlike passive USB-C cables, active Thunderbolt 4 cables contain integrated circuitry that regenerates and amplifies the signal, ensuring full data integrity and throughput over longer distances required for the 40 Gbps bidirectional bandwidth and dedicated PCIe data lanes. A passive USB-C cable, lacking these active components, cannot reliably support the complex signaling and high data rates an eGPU demands, leading to connection failure or limited functionality.

• ✗

  The eGPU requires a Thunderbolt 3 port, not Thunderbolt 4.

  Why it's wrong here

  Thunderbolt 4 is engineered with full backward compatibility for Thunderbolt 3 devices, ensuring seamless interoperability. This means that an eGPU designed for Thunderbolt 3 should function without issue when connected to a Thunderbolt 4 port, as the newer standard incorporates all the capabilities and protocols of its predecessor while offering additional enhancements like guaranteed 32 Gbps PCIe data and universal cable compatibility. Therefore, the eGPU requiring Thunderbolt 3 would not be a reason for it to fail on a Thunderbolt 4 port.

• ✗

  The laptop's Thunderbolt 4 port is not providing enough power.

  Why it's wrong here

  While Thunderbolt 4 ports are capable of delivering up to 100W of power, primarily for charging laptops or powering smaller peripherals, this is generally not a factor for external GPUs. External GPUs are high-power devices that typically include their own dedicated, robust power supply units (PSUs) to meet the substantial power demands of the graphics card and enclosure. The eGPU's independent power source means it does not rely on the host laptop's Thunderbolt port for operational power, making insufficient port power an irrelevant factor in its connectivity.

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