A desktop support technician is configuring a workstation connected to a high-end 4\text{K… — CompTIA A+ (Core 1 & Core 2)

A desktop support technician is configuring a workstation connected to a high-end $4\text{K}$ monitor requiring a resolution of $3840 \times 2160$ at $120\text{ Hz}$ with $10\text{-bit}$ HDR color depth. The display supports DisplayPort 1.4 and USB Type-C (DisplayPort Alt Mode) inputs. The workstation is connected to the monitor's USB-C port using a standard USB 3.2 Gen 1 (5 Gbps) Type-C cable, but the display output is restricted to $1920 \times 1080$ at $60\text{ Hz}$ , and built-in monitor USB hub speeds are severely degraded. Which of the following actions will resolve the display limitation while maintaining high-speed USB data passthrough for integrated peripherals?

Replace the existing cable with a certified 40 Gbps Thunderbolt 4 / USB4 cable supporting DisplayPort 1.4 HBR3 Alternate Mode.Answer
B
Connect the display using a passive USB-C to Single-Link DVI-D adapter cable.
C
Configure the graphics driver settings to force DisplayPort Alternate Mode over legacy USB 2.0 fallback pins.
D
Replace the connection with a standard High Speed HDMI cable connected through a passive USB-C to HDMI adapter.

Answer

Replace the existing cable with a certified 40 Gbps Thunderbolt 4 / USB4 cable supporting DisplayPort 1.4 HBR3 Alternate Mode.

DisplayPort Alternate Mode over USB Type-C relies on high-speed differential pairs within the cable. To drive a

4\text{K}

display at

120\text{ Hz}

alongside USB data passthrough, high bit rate 3 (HBR3) bandwidth is required. Replacing the basic 5 Gbps USB 3.2 cable with a certified 40 Gbps Thunderbolt 4 / USB4 cable provides full physical wire populating and shielding required to transmit uncompressed

4\text{K}

video at

120\text{ Hz}

while preserving USB peripheral throughput.

Step-by-Step Solution

Analyze resolution and bandwidth requirements

A resolution of

3840 \times 2160

(

4\text{K}

) at

120\text{ Hz}

with

10\text{-bit}

HDR color depth requires approximately 25.8 Gbps of uncompressed video bandwidth (HBR3 rating).

Standard USB 3.2 Gen 1 cables are limited to 5 Gbps and lack the high-speed lane wiring required for high-refresh

4\text{K}

video signals alongside data.

Evaluate USB Type-C physical connector vs. protocol capabilities

Physical USB Type-C cables vary significantly in internal pin populating and shielding, affecting supported protocols (DisplayPort Alt Mode vs. basic USB data).

To support both high-bitrate video (HBR3) and high-speed peripheral data over a single port, a cable certified for 40 Gbps (Thunderbolt 4 / USB4) is required.

Select the appropriate replacement cable

The certified 40 Gbps Thunderbolt 4 / USB4 cable supports full DisplayPort 1.4 Alt Mode bandwidth without compromising attached USB hub data transfer rates.

This cable meets all video bandwidth, refresh rate, and multi-stream data requirements.

Key Concept

DisplayPort Alternate Mode over USB-C and cable bandwidth limits

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