mediumMultiple Choice
220-1201 Practice Question: A user complains that their PC sometimes fails to…
A user complains that their PC sometimes fails to boot and displays a 'CMOS Checksum Error' message. After replacing the CMOS battery, the error persists. What motherboard component should you inspect next?
⚠ Common exam trap
The trap here is assuming the CMOS battery is always the culprit — CompTIA 220-1201 tests whether you can reason past the obvious battery fix to the next likely component when the symptom persists.
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 BIOS/UEFI chip
A persistent 'CMOS Checksum Error' after replacing the CMOS battery points to corruption or failure of the BIOS/UEFI firmware chip itself, since that chip stores the firmware and its checksum. If the battery is good but the checksum still fails, the NVRAM/EEPROM holding BIOS settings or the firmware image is likely damaged, requiring a BIOS reflash or motherboard replacement.
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 CPU socket pins
Why it's wrong here
Bent CPU socket pins prevent proper electrical contact between the CPU and the motherboard, which can lead to a complete failure to boot, system instability, or incorrect recognition of installed hardware components. While this is a severe hardware fault that can halt system operation, it does not directly corrupt the non-volatile CMOS memory or trigger a specific CMOS checksum error, which is a diagnostic message related to the integrity of stored BIOS settings.
- ✓
The BIOS/UEFI chip
Why this is correct
The BIOS/UEFI chip stores the system's firmware and the critical CMOS settings, along with a checksum used to verify their integrity. A failing BIOS/UEFI chip, or corruption within its firmware, can prevent the reliable storage or retrieval of these settings, causing the system to consistently report a CMOS checksum error. This occurs even when the CMOS battery is functional, as the underlying storage mechanism or the firmware itself is compromised.
- ✗
The RAM modules
Why it's wrong here
Faulty RAM modules typically cause system instability, random crashes, blue screens of death (BSODs), or prevent the system from booting entirely, often indicated by specific POST beep codes. While essential for system operation, issues with RAM do not directly affect the integrity of the non-volatile CMOS settings stored on the motherboard. Therefore, faulty RAM would not be the direct cause of a CMOS checksum error, which specifically relates to the corruption of stored BIOS configuration data.
- ✗
The power supply unit
Why it's wrong here
A failing power supply unit (PSU) delivers insufficient or unstable power to the system's components, leading to symptoms such as random shutdowns, intermittent reboots, or a complete failure to power on. While an unstable power environment can indirectly cause various issues, a failing PSU does not directly corrupt the CMOS settings or the BIOS firmware itself. Consequently, it would not typically manifest as a specific CMOS checksum error, which points to data integrity issues within the BIOS configuration.
Go deeper
Related to this question
Learn chapter
POST Error Messages
Key term
UEFI
UEFI (Unified Extensible Firmware Interface) is a modern firmware interface that initializes hardware and boots the operating system, replacing the older BIOS.
Key term
BIOS
BIOS (Basic Input/Output System) is the low-level firmware stored on a motherboard chip that initializes and tests hardware components before loading the operating system.
About these practice questions
Courseiva writes every 220-1201 question from scratch — 871 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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.