be quiet! System Power 11 550W power supply unit 20+4 pin ATX ATX Black

The be quiet! System Power 11 550W power supply unit delivers reliable, quiet power for value-oriented PC builds. It supports ATX 3.1 via a 20+4 pin motherboard connector, comes with fixed (non-modular) cabling and features an active 120 mm fan for temperature-controlled cooling. The unit is 80 PLUS Bronze certified and designed for AC 200–240 V, 50 Hz operation; its black finish is suitable for most system interiors.

Advantages

The System Power 11 550W combines proven reliability with low-noise operation thanks to an intelligently controlled fan. With 80 PLUS Bronze efficiency (about 89.7% peak) and multiple safety certifications, it provides stable power delivery for everyday desktop and entry-level gaming systems. Non-modular cabling simplifies installation and the ATX 3.1 compatibility ensures modern motherboard support.

Suitable for

• Home and office desktop PCs
• Entry-level gaming systems
• System upgrades requiring a 550 W PSU
• Builds where quiet operation is preferred

Key specifications

• Total power: 550 W
• Efficiency: 89.7% (80 PLUS Bronze)
• Motherboard connector: 20+4 pin ATX (ATX 3.1 compatible)
• Input: AC 200–240 V, 50 Hz
• Fan diameter: 120 mm, temperature-controlled
• Cabling: fixed (non-modular)
• Colour: Black
• Weight: 1.92 kg

How to use

Install the PSU into a compatible ATX case following the motherboard and case manufacturer guidelines. Connect the 20+4 pin ATX cable to the motherboard and attach the required peripheral connectors to drives and other components. Ensure the AC mains voltage matches the PSU rating (200–240 V) and route cables to avoid obstructing airflow. During initial power-up, verify that system fans and components receive stable power and monitor temperatures.

Recommendations

For reliable, quiet operation maintain adequate case ventilation and avoid blocking the 120 mm fan. Use this 550 W unit for systems whose combined component power draw stays within the PSU’s rated capacity; consider headroom for future upgrades.