be quiet! SFX L Power 600W PSU Review

With High Power's help, be quiet! recently joined the SFX-L market with one 500W model and a 600W version. Previously, the company only had two small form factor options available, so these latest PSUs double its reach.

SFX-L is preferred in many compact cases because it accommodates a fan as large as 120mm, enabling adequate airflow at lower speeds. Thus, it offers much lower noise output than power supplies sporting 80mm and 92mm fans.

Today's review covers the higher-capacity SFX L Power 600W. It's 80 PLUS Gold-certified, while on the Cybenetics scale it achieves ETA-B (88-91%) and LAMBDA-A (25-30 dB[A]) ratings. be quiet!'s SFX L Power 500W shares the same ETA rating, but generates less noise, allowing it to land in LAMBDA-A+ (20-25 dB[A]) territory.

According to be quiet!, the SFX L Power 600W is suitable for mini-ITX and compact gaming systems. Given four PCIe connectors and 600W of capacity, it's indeed able to support a capable gaming PC. However, the single EPS connector will surely limit compatibility with high-end mainboards.

The platform that High Power built for be quiet! is modern. It uses an LLC resonant converter on the primary side, along with synchronous rectification on the secondary side and DC-DC converters for generating the minor rails.


be quiet! employs fully modular cabling, which is the de-facto standard for high-end PSUs nowadays. Because of its SFX-L form factor, though, this unit can only deliver full power continuously at up to 40°C ambient. Of course, we'll push harder than that during our benchmark suite and see how the SFX L Power 600W responds.

A comprehensive list of protections features only lacks OCP for the +12V rail. However, in single-rail models like this one, over-power protection serves that purpose instead.

The 120mm cooling fan utilizes a fluid dynamic bearing, facilitating quiet operation and increased reliability. In fact, it offers a similar lifetime as double ball-bearing fans under normal environmental conditions. There is no semi-passive mode. But as long as the fan spins slowly under light and moderate loads, this won't be a problem. We actually prefer it, since heat doesn't build up inside of the PSU.

Three years of warranty coverage sounds pretty weak compared to other small form factor power supplies with longer guarantees. be quiet! needs to provide a five-year warranty, at least.

Power Specifications

Max. PowerAmps22225030.3
Total Max. Power (W)600

The +12V rail can deliver up to 50A of current, while the minor rails are strong enough, given their 105W maximum combined power. Moreover, the 5VSB rail is ample in light of this PSU's overall capacity.

Cables And Connectors

Modular Cables
DescriptionCable CountConnector Count (Total)Gauge
ATX connector 20+4 pin (300)1118AWG
4+4 pin EPS12V (405mm)1118AWG
6+2 pin PCIe (500mm+150mm)1218AWG
6+2 pin PCIe (405mm+150mm) 1218AWG
SATA (500mm+150mm+150mm)1318AWG
SATA (300mm+150mm+150mm)1318AWG
Four-pin Molex (300mm+200mm+200mm)1318AWG

It is great to see four PCIe connectors on an SFX-L PSU. Unfortunately, it seems as though there wasn't enough space on the modular board for a second EPS connector.

Cable length is naturally short, since SFX-L-based PSUs are built for small cases. The distance between connectors is ideal, though. We greatly appreciate the fact that the four-pin Molex connectors are installed 20cm from each other (even if we secretly wish High Power would include at least one more).

Again, compact dimensions prevent be quiet! from including more sockets on the modular panel. However, four connectors on the SATA and four-pin Molex cables could easily give you access to more connectors if needed.

Power Distribution

Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content