ITPEC FE Subject A April 2025 Question 8

MIPS Calculation — compute CPU performance in millions of instructions per second.

Given: clock frequency = 800 MHz, average CPI = 4 clock cycles per instruction.

Formula: MIPS = Clock Frequency (MHz) / CPI

Step-by-step:
- Clock frequency = 800 MHz = 800 × 10⁶ cycles/sec
- CPI (Cycles Per Instruction) = 4
- Instructions per second = 800 × 10⁶ / 4 = 200 × 10⁶
- MIPS = 200

Why not others:
- (a) 0.2 — incorrect unit conversion
- (b) 20 — off by a factor of 10
- (d) 3,200 — multiplied instead of dividing (800 × 4)

Key rule: MIPS = MHz / CPI. When frequency is already in MHz, just divide by CPI directly.

AI-generated — may contain errors