The Be Quiet! SFX-L Power 500W PSU Review: Powerful, Small, & Still Quiet?
by E. Fylladitakis on November 13, 2017 8:30 AM ESTCold Test Results (Room Temperature)
For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.
The efficiency of the Be Quiet! SFX-L Power 500W PSU was surprisingly good, even when compared to ATX 80Plus certified models. Across the nominal load range (20% to 100% of the unit's capacity), the SFX-L PSU meets the 80Plus Gold certification standards with ease. The average efficiency across the nominal load range is 91.5%, which is exceptional for an SFX-L PSU. It also is particularly efficient when handling low loads, with the conversion efficiency surpassing 86% with a load of just 50 Watts.
The thermal performance of the Be Quiet! SFX-L Power 500W is very good, rewarding Be Quiet! for their choice to extend the chassis and go with a 120 mm fan. The temperature readings are low, even comparable to those of high-end ATX units, yet not astonishing. The fan’s airflow can only do so much when the heat dissipation surface is limited. Better heatsinks could have a dramatic effect here.
Our sound pressure readings were good but probably not as good as Be Quiet! would have liked them to be. There is no “semi-fanless” mode or advanced thermal control circuitry here – the fan starts immediately alongside with the PSU and its speed depends on the unit’s internal temperature. The Be Quiet! SFX-L Power 500W is practically inaudible at low loads but can be noticed if the entire room is entirely quiet. As the load increases over 300 Watts, the fan will start increasing its speed exponentially, making the PSU clearly audible when heavily loaded.
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u.of.ipod - Monday, November 13, 2017 - link
Nice review! Any plans to review the new Silverstone SFX models with 500w/650w capacities?jrs77 - Monday, November 13, 2017 - link
I have the Silverstone SFX-L 500, which seems to be more or less the same PSU as this one.Samus - Tuesday, November 14, 2017 - link
Ditto. Great PSU. I've had a number of SFX Silverstone PSU's over the years and all have been excellent.MrSpadge - Monday, November 13, 2017 - link
You're clearly putting effort into the reviews and graphs. Yet you still don't mention the voltage at which the units were tested for efficiency. I know it can be found in that 2014 pipeline post you linked to. But how many readers are not going to look that up and may expect testing at 110 V, because they're from the US, and be disappointed when they find out the good numbers shown by AT don't match their reality?meacupla - Monday, November 13, 2017 - link
Oh, nice. Someone thought to use a FDB fan in the PSU.Other pricey options out there, like Corsair's SF line, still insist on using sleeve bearings, for some reason.
Samus - Tuesday, November 14, 2017 - link
They wanted it to be quiet. They didn't say anything about it lasting more than 50,000 hours ;)PeachNCream - Tuesday, November 14, 2017 - link
That's still almost 6 years of non-stop operation! (o.O) I'm sure there's cases where people are running decade old power supplies and someone reading the comments will say as much, but if you turn your PC off when you're not using it or just run it for 8 hours a day, 50,000 hours could be like 17 years.Brian_R170 - Tuesday, November 14, 2017 - link
Not all FDBs are the same (Not sure which one is actually used in the Globe Fan in this PSU) and not all are actually manufactured better than sleeve bearings.Corsair's SF-series and Enermax Revolution PSUs with sleeve bearings are semi-passive. For many users, that will translate to lower noise and longer life than an FDB fan that runs all the time. I'm somewhat disappointed that the Be Quiet! doesn't have a semi-passive mode since "acoustics performance is of utmost importance to the company".