hardMultiple ChoiceObjective-mapped
220-1201 Practice Question: That their 4K monitor connected via DisplayPort…
A user reports that their 4K monitor connected via DisplayPort 1.2 only shows a 30Hz refresh rate at native resolution, causing mouse movement to feel laggy. The monitor supports 60Hz at 4K. What is the most likely cause?
⚠ Common exam trap
CompTIA often tests the misconception that the refresh rate issue is caused by a monitor setting or GPU limitation, when in fact the cable's bandwidth rating is the critical bottleneck that candidates overlook.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The DisplayPort cable is only rated for DisplayPort 1.1
DisplayPort 1.2 has sufficient bandwidth (17.28 Gbps) to support 4K at 60Hz with 8-bit color. However, a cable only rated for DisplayPort 1.1 is limited to 8.64 Gbps, which cannot handle the full data rate required for 4K at 60Hz, forcing the signal to drop to 30Hz. This is the most likely cause because the cable is a physical bottleneck, even though the GPU and monitor both support the higher refresh rate.
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The monitor's firmware is outdated
Why it's wrong here
Outdated monitor firmware is an unlikely cause for a specific refresh rate limitation from 60Hz to 30Hz on a 4K display. Firmware issues typically manifest as more severe problems, such as complete display failure, incorrect Extended Display Identification Data (EDID) reporting, or general instability, rather than a precise bandwidth-related bottleneck that forces a lower refresh rate. This symptom points more directly to a physical hardware limitation in the display chain.
- ✗
The graphics card does not support 4K at 60Hz
Why it's wrong here
While an extremely old or low-end graphics card might not support 4K at 60Hz, most modern GPUs, even those a few years old, are equipped with DisplayPort 1.2 or newer, which provides sufficient bandwidth for 4K 60Hz. If the graphics card were the sole limitation, it might not even output 4K resolution at all, or the issue would likely be more widespread across various resolutions, making a cable bottleneck a more common and specific cause for this particular symptom.
- ✓
The DisplayPort cable is only rated for DisplayPort 1.1
Why this is correct
A DisplayPort 1.1 cable has a maximum effective data rate of 8.64 Gbit/s. However, displaying 4K resolution (3840x2160) at a 60Hz refresh rate with standard 8-bit color depth requires approximately 12.54 Gbit/s of bandwidth. Since the DP 1.1 cable cannot transmit data at this higher rate, the display system automatically negotiates down to a lower refresh rate, such as 30Hz, to fit within the cable's limited bandwidth capacity.
- ✗
The monitor's refresh rate is set to 30Hz in the display settings
Why it's wrong here
If the monitor's refresh rate were merely set to 30Hz in the display settings, the user would typically still see 60Hz (or higher) as an available option if the entire display chain supported it. The user's report that it 'only shows 30Hz' strongly indicates that 60Hz is not even presented as a choice, which points to a fundamental bandwidth limitation imposed by a component like the cable or graphics card, rather than a user configuration preference.
Go deeper
Related to this question
About these practice questions
One of 972 original 220-1201 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.