hardMultiple ChoiceObjective-mapped
FC0-U71 Practice Question: A computer has 8 GB of RAM installed, but the…
A computer has 8 GB of RAM installed, but the operating system reports only 7.9 GB usable. What is the most likely reason for this discrepancy?
⚠ Common exam trap
Many candidates confuse OS overhead (Option A) with hardware reservation, or they incorrectly assume a 32-bit OS limitation (Option C) when the system clearly reports more than 4 GB of usable RAM.
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
✓
Some RAM is reserved for hardware devices
The most likely reason is that some RAM is reserved for hardware devices. This is a standard behavior where system resources, such as memory-mapped I/O (MMIO), are allocated to hardware components like the GPU, network adapters, and PCIe devices. This reservation reduces the total usable RAM reported by the operating system, even though 8 GB is physically installed.
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 operating system itself uses too much RAM
Why it's wrong here
OS overhead is typically much less than 0.1 GB.
- ✓
Some RAM is reserved for hardware devices
Why this is correct
Integrated graphics or other hardware may reserve a portion of RAM.
- ✗
The operating system is 32-bit
Why it's wrong here
A 32-bit OS would limit usable RAM to about 4 GB, not 7.9 GB.
- ✗
The RAM is not installed in dual-channel mode
Why it's wrong here
Dual-channel affects performance, not usable capacity.
Go deeper
Related to this question
About these practice questions
Courseiva writes every FC0-U71 question from scratch — 988 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 by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This FC0-U71 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 FC0-U71 exam.