Introduction

We would like to thank Super Flower for supplying the review sample.


After the Leadex III ARGB Gold 850 W, the strongest member of the line, I thought it would be interesting to take a look at the smallest member of the line with 550 W maximum power output. The big difference between the RGB and non-RGB Leadex models is the massive price gap, next to the RGB lighting, lack of ECO mode (non-RGB Leadex III units have two ECO modes), and different cable set.


Currently, the Leadex III ARGB 550 W is sold for €109.90 incl. VAT by Caseking, while the plain Leadex III with a similar capacity costs €85.90 incl. VAT from the same store.


The backside has the cube-shaped modular sockets and a socket for connecting the PSU to the mainboard for lighting control (if the latter is compatible, of course).

Specifications

On the Cybenetics scale, the PSU makes the ETA-A and LAMBDA-A+ efficiency and noise certifications.

Cables and Connectors

There are in-cable caps on the ATX, EPS, and PCIe cables. This is bad news for most users since these caps can make cable-routing harder than it has to be. That having been said, because of the low capacity, most gauges are 18AWG instead of the 16AWG Super Flower uses in stronger PSUs, so they are flexible enough.


The cables are long enough for the PSU's capacity. However, an ATX cable with a length of over 600 mm would have been nice. The distance between peripheral connectors, especially the 4-pin Molex ones, is too short at 100 mm as they should at least be 150 mm apart.

Component Analysis

The Leadex III platform is among the best analog platforms available today. Super Flower generally used good parts, although I would like to see more electrolytic caps with a higher lifetime, like Chemi-Con's KY caps. On the primary side, we find the typical stuff: a half-bridge topology supported by an LLC resonant converter. On the secondary side, a synchronous design generates the +12 V rail, while the minor rails are generated through a pair of DC-DC converters.


The transient filter is complete and does a good job, as our EMI test results show.


The parts shown in the photos above provide protection against voltage surges and high inrush currents.


The PSU uses a single bridge rectifier, which I couldn't identify without desoldering it.


The APFC converter uses a pair of Infineon FETs and an STMicroelectronics boost diode. The PFC controller is a proprietary SF IC.


The main switching FETs are arranged in a half-bridge topology.


A resonant converter boosts efficiency by lowering switching losses.


The FETs regulating the +12 V FETs are installed on a pair of small heat sinks.


Japanese manufacturers provide the filtering caps. However, only six are from Chemi-Con's KY line. The KZE and especially the KMG caps have a low lifetime, and the same goes for Nichicon's RZ line. Besides electrolytic caps, nine polymer caps also help with ripple filtering.


These are the VRMs that generate the minor rails (5 V and 3.3 V).


This is the standby circuit—it is very efficient, which is a major improvement over the Leadex II line.


A number of polymer and electrolytic caps installed on the face of the modular board provide an extra ripple-filtering layer.


Soldering quality is decent, but definitely not among the best I have seen.


The fan measures 130 mm across and uses a fluid dynamic bearing. I don't like the vertical fan-control board because it can break off at the base if you don't pay attention while removing the fan header.

Test Setup