be quiet! System Power 11 550W 20+4 Pin ATX PSU Black

be quiet! System Power 11 550W | ATX 3.1 Entry-Level PSU

The be quiet! System Power 11 550W power supply unit 20+4 pin ATX ATX Black is designed for value-focused builders who refuse to compromise on reliability. This unit delivers essential stability for office PCs and entry-level gaming rigs. It features ATX 3.1 compatibility and a temperature-controlled fan for quiet operation. Because it targets practical builds, it offers a solid foundation without unnecessary extras. You get proven performance for standard UK systems.

Slim Specs Table

ATX 3.1 and PCIe 5.1 Compatibility

This PSU meets the latest ATX 3.1 and EPS 2.92 standards. It handles power excursions common in modern graphics cards. Because it supports the new 12-pin PCIe connector, it is ready for current and next-gen hardware. In practice, this means your system stays stable during sudden load spikes. You avoid unexpected shutdowns during intensive tasks.

Quiet 12 cm Rifle Bearing Fan

The unit uses a single 12 cm fan with Rifle bearing technology. Fan speed adjusts from 0 to 1800 RPM based on temperature. So, it remains silent during light workloads and cools effectively under load. The noise level is rated at 24.2 dB, which is very quiet for a active cooling solution. This helps maintain a distraction-free environment.

Robust Power Protection and Efficiency

It delivers 550 W across a single +12V rail, providing 45.83 A for demanding components. The unit includes comprehensive protection features: Over current, Over power, Over voltage, Overheating, Short circuit, Surge & inrush, and Under voltage. Efficiency reaches 89.7%, reducing wasted energy and heat. Also, the power factor is 0.98, indicating efficient AC to DC conversion. This ensures long-term reliability for your build.

Essential Connectivity for UK Builds

The PSU includes a 20+4 pin ATX motherboard connector and a 4+4 pin CPU connector. It provides two 6+2 pin PCIe connectors for graphics cards. With five SATA and one Molex connector, you can power drives and accessories. However, the cabling is non-modular, so unused cables remain attached. Confirm your case has space for cable management.

Box contents

• be quiet! System Power 11 550W PSU
• Fixed cables (ATX, PCIe, SATA, etc.)
• Mounting screws
• Cable ties

Check before you buy

• Confirm your UK wall socket provides 200-240 V AC input.
• Verify your case supports standard ATX form factor (150 x 86 x 140 mm).
• Check you have physical space for non-modular cable routing.
• Ensure your components require no more than 550 W total power.

Frequently Asked Questions

Q: Is this power supply compatible with UK mains voltage?

A: Yes, it supports 200-240 V AC input, standard for UK homes.

Q: Does it include the new 12-pin PCIe connector?

A: Yes, it has one 12-pin PCIe power connector for modern graphics cards.

Q: Is the fan always spinning?

A: No, the fan stops at low loads for silent operation.

Q: Are the cables modular?

A: No, this is a non-modular PSU; cables are fixed.

Q: What protection features are included?

A: It has over current, over voltage, overheat, and short circuit protection.

The Consultant’s verdict & warranty

This unit is ideal for UK users building a quiet, reliable office PC or entry-level gaming system on a budget. It offers essential ATX 3.1 compliance and solid protection features without premium cost. Choose this if you value silence and proven stability over modular cabling. Covered by the standard Manufacturer Warranty.