Power Management
Why is the energy-delay product (EDP) sometimes preferred over energy alone in evaluating low-power designs?
- AEnergy alone can favor designs made extremely slow to save energy, so EDP evaluates the balance with speed
- BEDP is simpler to compute than energy
- CUsing EDP always makes power zero
Show answer and explanation
Answer: A. Energy alone can favor designs made extremely slow to save energy, so EDP evaluates the balance with speed
Lowering voltage and frequency drastically shrinks energy per computation but makes processing impractically slow. The energy-delay product multiplies energy per operation by the time it takes, so cutting energy at the cost of a large slowdown does not improve the score, allowing designs to be compared on the balance of performance and efficiency. When speed matters even more, a metric multiplying by the square of time is used.
- A. Correct. Smaller is better for both energy and time.
- B. It adds a multiplication; it is not simpler.
- C. Changing the metric does not change power.