At long last, be quiet! is active in the SFX-L market. This form factor combines compact dimensions and notably less noise than standard SFX, since it can accommodate 120mm (rather than just 92mm) fans. Moreover, the smaller a PSU's platform, the more difficult it becomes to cool down effectively. Crowded PCBs restrict airflow, after all. And this problem gets worse as capacity increases. So naturally, SFX-L-based power supplies enjoy a big advantage over SFX ones. Since mini-ITX cases aren't compatible with the larger ATX PSUs most commonly found in desktop PCs, SFX and SFX-L are critical in enabling compact systems.
The cooperative effort between be quiet! and High Power looks interesting enough: the OEM has plenty of experience designing and manufacturing high-density PSUs, while be quiet! enjoys a great reputation in the quiet computing market. The resulting platform in be quiet!'s SFX-L models doesn't offer ground-breaking performance, but it fares well in our benchmarks and, on top of that, is efficient. Thanks to the SFX L Power 600W's 120mm fan, high efficiency, and optimized fan profile, overall noise is low at normal ambient temperatures. Even under stressful conditions, when the temperature rises over 45°C, the fan's noise remains reasonable. Obviously, be quiet! paid a lot of attention to this model's acoustic footprint, and the outcome is excellent. So far, only FSP's SFX-based SDA600 is quieter.
In the performance section, load regulation and efficiency are in line with our expectations, and we appreciate the fact that all protection features are present. We would like to see a lower over-power protection triggering point, since 810W is pretty aggressive for such a compact platform. This power level might be feasible under normal operating temperatures. However, in warmer environments, the PSU's components endure much more stress, reducing their useful life. Thankfully, over-temperature protection is set at a normal level, so that should effectively protect the PSU.
When it comes to ripple suppression, we aren't fully satisfied. We would like to see lower ripple at +12V and 3.3V. Moreover, the lack of an NTC thermistor is a huge disappointment since it allows for very high inrush currents during the PSU's start-up phase. We suspect that improving the 5VSB rail's efficiency was justification for the NTC thermistor's omission; when the PSU operates normally, you can bypass this thermistor with a relay, but that isn't an option in standby.
With a price tag around $120, be quiet!'s SFX L Power 600W is an expensive power supply in a competitive market. If the company wants a larger share of the SFX-L pie, it'll need to make this model more affordable and extend its warranty to five years, if possible. One of the biggest problems with long warranties is their relationship to cooling fan choice. The SFX L Power 600W employs an FDB-based fan. However, we only found a single gasket and not two, meaning that its lubricant will evaporate sooner compared to higher-quality alternatives. Given the lack of a semi-passive mode as well, this might be the reason for be quiet!'s three-year warranty.
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