Zalman ATX 500 Power Supply 500-HP Plus This power supply is 80 PLUS Bronze certified with 82% minimum/88% maximum efficiency (230VAC, Typical Load) incorporating a high switching frequency & low power loss circuitry design, and guarantees higher efficiency compared to non-certified products. Modular cables facilitate simplified cable management and optimal airflow through the computer enclosure for increased cooling performance. Ultra quiet 120mm Sleeve Bearing fan increases airflow while minimizing noise for a superbly quiet computing environment.