A desktop support technician is configuring a creative workstation that requires driving a… — CompTIA A+ (Core 1 & Core 2)

A desktop support technician is configuring a creative workstation that requires driving a single monitor at a resolution of $3840 \times 2160$ ( $4K$ ) with a $120\text{ Hz}$ refresh rate. The GPU features DisplayPort 1.4 and HDMI 2.0 outputs, and the monitor has matching DisplayPort 1.4 and HDMI 2.0 inputs. When connected using a high-speed HDMI 2.0 cable, the display options in the operating system max out at $3840 \times 2160$ at $60\text{ Hz}$ . Replacing the HDMI cable with a standard DisplayPort 1.4 cable immediately allows the technician to select $3840 \times 2160$ at $120\text{ Hz}$ . Which of the following best explains why replacing the cable resolved the refresh rate limitation?

DisplayPort 1.4 provides higher maximum data throughput ( $32.4\text{ Gbps}$ ) compared to HDMI 2.0 ( $18.0\text{ Gbps}$ ), which is necessary to drive uncompressed 4K video at 120 Hz.Answer
B
HDMI 2.0 requires an external active inline powered adapter to transmit refresh rates exceeding 60 Hz regardless of display resolution.
C
HDMI cables transmit analog display signals at high resolutions, whereas DisplayPort cables carry digital signals capable of higher refresh speeds.
D
The display monitor required Thunderbolt DisplayPort Alternate Mode protocol encapsulation, which is only supported over DisplayPort physical connectors.

Answer

DisplayPort 1.4 provides higher maximum data throughput compared to HDMI 2.0, satisfying the bandwidth requirement for 4K video at 120 Hz.

The correct option correctly highlights that DisplayPort 1.4 offers up to 32.4 Gbps of total bandwidth (25.92 Gbps uncompressed payload throughput), which exceeds the requirement for 4K video at 120 Hz. In contrast, HDMI 2.0 is limited to 18.0 Gbps (14.4 Gbps payload), restricting 4K output to 60 Hz unless chroma subsampling or HDMI 2.1 is used.

Step-by-Step Solution

Calculate video bandwidth requirement

Uncompressed

3840 \times 2160

120\text{ Hz}

(8-bit color) requires approximately

25.8\text{ Gbps}

of raw data throughput.

Bandwidth increases proportionally with pixel count and refresh rate.

Compare interface specification throughputs

HDMI 2.0 maximum bandwidth is

18.0\text{ Gbps}

(

14.4\text{ Gbps}

data rate limit), capping it at

4K

60\text{ Hz}

. DisplayPort 1.4 maximum bandwidth is

32.4\text{ Gbps}

(

25.92\text{ Gbps}

data rate limit).

HDMI 2.0 lacks sufficient data throughput for uncompressed 4K at 120 Hz.

Select the correct technical rationale

DisplayPort 1.4 provides the necessary bandwidth natively over standard DisplayPort cabling.

Direct DisplayPort connection eliminates the interface bandwidth bottleneck.

Key Concept

Display cable bandwidth limitations and specification differences between HDMI 2.0 and DisplayPort 1.4

Estimated Time:1m 30s

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