ITPEC IP October 2025 Question 10

Cache memory — a small, fast memory between the CPU and main memory that holds recently used data and instructions.

Main memory (DRAM) is much slower than the CPU. Cache memory (SRAM) keeps copies of data the CPU has just used or is likely to use next. When the data is in the cache (a hit), the CPU reads it at cache speed; only on a miss does it wait for main memory. With hit ratio h, cache access time C and main memory access time M, the effective access time is h × C + (1 − h) × M, close to C when h is high.

Answer (c)

Why not others:

• •(a) SSD — auxiliary storage using flash memory; it speeds up access to stored files compared with an HDD, not the CPU's access to main memory
• •(b) Virtual memory — uses auxiliary storage to make main memory look larger; it increases capacity, and swapping pages to disk makes access slower, not faster
• •(d) Defragmentation — rearranges a file's scattered blocks on a disk so that files read faster; it does not involve main memory

Key rule: Cache memory bridges the speed gap between the CPU and main memory; virtual memory extends main memory's capacity with auxiliary storage.

Computer Component · AI-written, may contain errors