Shutdown Under Load? Check Power Supply Capacity
A technician is troubleshooting a desktop computer that shuts down unexpectedly after about 15 minutes of running a graphics-intensive application. The computer operates normally during light use, such as web browsing and word processing. The technician has verified that all cooling fans are spinning and that the CPU and GPU temperatures are within normal ranges. Which of the following is the MOST likely cause of the issue?
Quick Answer
The pattern in this question is load-dependent failure: the system is completely stable during light tasks like browsing and word processing but fails specifically when the GPU and CPU are pushed hard for an extended period, with temperatures and fans confirmed normal throughout. This rules out a cooling or airflow problem, since overheating has already been checked and cleared, and points instead toward the power delivery system rather than thermal management. Graphics-intensive workloads create large, rapid spikes in current draw as the GPU ramps its power consumption, and if the power supply's rated capacity or the strength of its 12V rail is marginal for the system's components, its overcurrent or undervoltage protection circuitry will trip once demand exceeds what it can reliably deliver, causing an abrupt shutdown rather than a gradual slowdown. Because the shutdown happens only under sustained heavy load and never during idle or light use, the failure is tied directly to peak power demand rather than any single component being defective. Whenever a system runs perfectly under light use but shuts down specifically during graphically or computationally intensive tasks, with temperatures confirmed normal, treat insufficient power supply capacity as the leading explanation before suspecting individual hardware components.
⚠ Common exam trap
It's easy for candidates to assume overheating is the only cause of shutdowns under load, but the question explicitly states temperatures are normal, forcing the test-taker to recognize that power delivery—not thermal—is the hidden variable.
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
✓
Insufficient power supply capacity
The symptom of a computer shutting down under heavy GPU/CPU load after a consistent time interval, despite normal temperatures and fan operation, strongly points to the power supply unit (PSU) being unable to deliver sustained peak current. Graphics-intensive applications draw high transient power spikes; if the PSU's rated capacity is insufficient or its 12V rail is degraded, the overcurrent protection (OCP) or undervoltage protection (UVP) will trip, causing an abrupt shutdown. The fact that light workloads run fine confirms the issue is load-dependent, not a thermal or component failure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Failing memory module
Why it's wrong here
Failing memory typically produces random crashes, blue screens, or POST errors regardless of workload, not shutdowns tied specifically to graphics-intensive use after 15 minutes. It is tempting because memory faults cause instability, but the workload-correlated timing points to power delivery, such as an inadequate or failing PSU under GPU load.
- ✗
Corrupt operating system files
Why it's wrong here
Corrupt OS files can cause crashes or blue screens, but they do not normally cause a complete power loss. The system shuts down cleanly as if the power was cut, pointing to a hardware power issue.
- ✓
Insufficient power supply capacity
Why this is correct
Sustained graphics load draws far more current than light browsing, so a power supply near its limit shuts down under that demand while temperatures remain normal. Insufficient wattage or a failing rail explains the load-correlated shutdown, unlike thermal throttling, which the verified temperatures already exclude.
- ✗
Faulty motherboard
Why it's wrong here
A faulty motherboard usually causes failures at boot or random instability, not reproducible shutdowns only under sustained graphics load. It is tempting because motherboards regulate power delivery, but the workload-specific timing indicates the PSU cannot sustain the increased GPU current draw, which is the actual fault.
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Same concept, more angles
2 more ways this is tested on 220-1101
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user reports that their desktop computer shuts down unexpectedly without warning, typically when playing graphics-intensive games or running video rendering software. The technician has verified that the CPU cooler is properly seated with fresh thermal paste and that all fans spin freely. The event logs show a kernel-power error 41. Which of the following should the technician do NEXT?
medium- A.Replace the RAM modules with known-good ones
- B.Run a hard drive diagnostic test
- ✓ C.Test the power supply under load or replace it with a known-good unit
- D.Update the graphics card driver to the latest version
Why C: Kernel-power error 41 indicates an unexpected loss of power. Under heavy GPU load, a failing or underrated power supply can drop voltage or current, causing the system to shut down instantly. Since the CPU cooling is verified, the power supply is the most likely culprit.
Variation 2. A user reports that their desktop computer shuts down unexpectedly when running resource-intensive applications like video editing. The technician has cleaned the dust from the heatsink and fans, verified that all fans are spinning, and monitored temperatures. The BIOS reports CPU temperature as 35°C idle and 70°C under load, which are within normal specifications. The system has a dedicated graphics card that requires a 6-pin PCIe power connector, and the power supply is a 450W unit that came with the computer case. Which of the following is the MOST likely cause?
medium- A.The CPU thermal paste has degraded and needs to be reapplied
- ✓ B.The power supply is inadequate for the system's peak power draw
- C.The motherboard has a faulty capacitor
- D.The RAM is incompatible with the motherboard
Why B: The system shuts down under load despite normal CPU temperatures and clean cooling. A 450W power supply that came with a case is typically a low-quality unit with limited capacity. The dedicated graphics card, especially during video editing, can draw significant power, and the total system peak draw likely exceeds the PSU's capacity, causing it to trip overcurrent protection or shut down.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.