CPU, Memory, and Storage Differences | IT Passport Exam Prep

The Five Major Computer Components

The CPU integrates the control unit and the arithmetic logic unit. Storage devices use a hierarchical structure to balance speed and capacity. We'll explain this hierarchy in more detail later.

Key CPU Parameters

Clock Frequency (Hz)

Clock frequency indicates how many instructions a CPU can process per second. For example, 3 GHz means it can process 3 billion instructions per second. However, the number of cycles required to execute a single instruction also affects processing speed.

Number of Cores

The number of cores indicates how many independent processing units exist within a single CPU. Modern CPUs commonly use multi-core configurations like 4 cores or 16 cores to enable parallel processing. The number of threads can exceed the number of cores, thanks to hyper-threading technology.

Cache Memory

Cache memory is high-speed memory located inside the CPU, organized into L1, L2, and L3 levels. It temporarily holds data from main memory to speed up CPU processing.

Memory Hierarchy

Higher levels in the hierarchy are faster, smaller in capacity, and more expensive. Conversely, lower levels are slower but offer larger capacity at lower cost.

Main Memory (RAM)

The mainstream type of main memory is DRAM, which requires periodic rewriting called refresh. In contrast, SRAM, used for cache, does not need refreshing and is faster than DRAM.

Auxiliary Storage

HDDs use a mechanical recording method, offering low cost and large capacity but slower performance. SSDs use semiconductor memory, providing high speed and impact resistance, but are more expensive than HDDs. Cloud storage services like S3 and Google Drive are also used.

Key Points for the IT Passport Exam

Be sure to memorize the functions and specific examples of the five major components. Understanding the memory hierarchy is easier when organized along the three axes of speed, capacity, and cost. Differences between HDDs and SSDs, as well as the unit for clock frequency (Hz), are frequently tested.

Typical Past Exam Question Patterns

• "What is the purpose of cache memory?" type → Speeding up main memory access
• "Which statement correctly describes the difference between SSDs and HDDs?" type

Related Terms

• Virtualization technology (Virtualization, Containers, Docker)
• OS and middleware (OS and Middleware)
• Number base conversion (Binary, Hexadecimal, and Logic Operations)

Study Tips

Start by memorizing the five major components, then move on to the internal structure of the CPU for an efficient approach. Compare the memory hierarchy along the three axes of speed, capacity, and cost. Understanding the difference between HDDs and SSDs—focusing on whether they are mechanical or semiconductor-based—will help on the exam.

Summary

Mastering the five major components, CPU structure, and memory hierarchy will stabilize your score in the hardware domain. For more practice in the Technology area, check out the Technology Summary. To try a full-length practice test, use the Mock Exam.