Super Flower Leadex Gold 550W PSU Review

Super Flower has made quite an impact on the PSU market. Its Leadex platform enjoys huge popularity, both under SF's brand name and other companies like EVGA. The newest Leadex Gold-rated PSU with 550W capacity is on our test bench today.

Early Verdict

Super Flower's SF-550F14MGA PSU is overall a silent unit, at least under normal ambient temperatures, with excellent ripple suppression, tight load regulation and high efficiency. Its major downside is the low hold-up time and some users might not like the caps choice in the secondary side, where besides Japanese caps several CapXon caps are also used.


  • +

    Full power at 47 °C • Efficient • Load regulation • Ripple suppression • Silent • Fully modular • LED-lit connectors • Semi-passive operation • Long Warranty


  • -

    Hold-up time • 3.3V rail's performance in Transient Tests • Uses several CapXon filtering caps • 5VSB efficiency • 20AWG gauges on the EPS and PCIe cables

Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

Super Flower SF-550F14MG Power Supply Review

Super Flower recently released a new 550W Leadex power supply. In addition to its Gold-rated efficiency, this PSU offers modular cables with cube-shaped and LED-lit connectors, which we usually only see in the company's high-end offerings. On top of that, the SF-550F14MG employs a semi-passive mode that can be disabled if you'd prefer the fan to spin continuously. Speaking of the fan, strangely enough it isn't the same one used in Super Flower's Platinum Leadex PSU with the same capacity (SF-550F14MP).

Over in Europe, the price of this unit is very competitive given its high-end features. As you might already know, Super Flower doesn't have a retail presence in the U.S., but you can still find the company's products under the EVGA brand. In essence, EVGA's 550 G2 uses the same platform as the SF-550F14MG PSU, and is available domestically. However, the PSUs are not identical; a couple of notable differences include a smaller fan and Super Flower's cube connectors on the modular cables. There's another crucial distinction between the platforms, and we'll talk more about it on page three.

Lower-capacity PSUs are becoming more popular in the face of Intel's efficient architecture's and Nvidia's Maxwell family of GPUs. A 550W power supply can easily work in a PC equipped with a GeForce GTX 980 Ti and a potent host processor. If you really want to live on the edge, drop in a Radeon R9 390 GPU, which peaks around 370W at stock clocks. But you'll push that 550W PSU to its limit, reducing efficiency and the hardware's useful life. Generally, you want your PSU operating at 40 to 50 percent of its max-rated capacity, since that's where efficiency is often best.


As mentioned, the SF-550F14MG satisfies the 80 PLUS Gold requirements. It delivers its full power continuously at up to 50 °C ambient. On top of that, it fully supports the S6 and S7 sleep states that newer Intel CPUs support. Only basic protection features are enabled. Over-temperature protection is missing. Over-current protection is also missing, but it's not essential in a single-rail PSU, where over-power protection intervenes when something goes wrong.

A low-speed, double ball-bearing fan is used for cooling and thanks to the semi-passive mode it is able to offer a very quiet operation, especially under light and moderate loads. Given its low capacity, the SF-550F14MG could be even smaller, physically. However, a depth of 16.5 centimeters won't be a problem in most cases. Finally, you get a long five-year warranty. EVGA's is even better at seven years, so it's be nice if Super Flower matched the 550 G2's guarantee.

Power Specifications

Swipe to scroll horizontally
Max. PowerAmps222245.830.5
Total Max. Power (W)550

The +12V rail is strong enough with almost 46A of maximum current output. The minor rails provide enough juice as well, taking into account the PSU's capacity. Finally, the 5VSB rail is a little stronger than we typically see.

Cables And Connectors

Swipe to scroll horizontally
Modular Cables
DescriptionCable CountConnector Count (Total)
ATX connector 20+4 pin (600mm)11
4+4 pin EPS12V (700mm)11
6+2 pin PCIe (600mm+120mm)12
6+2 pin PCIe (600mm)11
SATA (540mm+125mm+125mm+125mm)28
SATA (540mm+125mm) / four-pin Molex (125mm+125mm)12 / 2
Four-pin Molex (540mm+125mm+125mm) / FDD (+125mm)13 / 1

The unit comes with three PCIe connectors and a single EPS connector. We would prefer if it had four PCIe connectors, but Super Flower likely thought that'd be overkill for a 550W PSU. In addition, it'd be nice to have a second EPS connector or at least a four-pin ATX12V connector, since some mainboards need them, and it's just not safe to use four-pin Molex adapters for extra EPS/ATX connectors. Thankfully, you get plenty of SATA and peripheral connectors.

Cable length is satisfactory and the distance between connectors is adequate, although it might be useful to have more space between the four-pin Molex connectors. The components that use them (like system fans) are usually installed far from each other, so it'd be nice to have lots of room to stretch. On the other hand, hard drives and SSDs are usually installed right next to each other, so the SATA connectors don't need to be far from each other.

This is a lower-capacity unit, so Super Flower decided that a mix of 22-, 20- and 18-gauge wires on the main ATX cable would work. Don't anticipate any problems there; the cables don't have to deal with lots of power, so large voltage drops won't be an issue. But the ATX spec does state that at least 18-gauge wires should be used for power transfer and only the sense wires can be thinner. We also found a mix of 18- and thinner 20-gauge wires on the EPS and PCIe cables, which normally should consist of only 18-gauge wire. All peripheral cables employ the normal 18-gauge wires.

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: Power Supplies 101
MORE: How We Test Power Supplies
MORE: All Power Supply Content

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • blazorthon
    Granted the EPS and PCIe wires don't see very high current in most situations (especially the EPS with Haswell or Skylake CPUs), I hardly ever see other PSUs using thinner gauge wires, so I can't imagine it saving enough money to be worth going thinner than the recommended 18 gauge wires most other PSUs have regardless of capacity.
  • Quaddro
    Why crapxon?
    I'm tired to see bulged crapxon..

    If this one use jap caps, it'll be absolutely perfect..
  • iam2thecrowe
    I wonder if it's just a faulty unit with the low hold up time?
  • Mac266
    I wonder if it's just a faulty unit with the low hold up time?

    My first thought too
  • Aris_Mp
    The APFC caps have the advertised capacity so there is nothing wrong with this PSU.
  • mctylr
    Unfortunately, the bridge rectifier's markings are on its hidden side, and we try to avoid desoldering these type of parts since they are extra sensitive to increased heat

    Huh? Since when are bridge rectifiers particularly heat sensitive? I would say that bridge rectifiers are not worth the hassle to desolder, unless you suspect it was an underrated part.

    APFC controller is an NCP1653A provided by ON Semiconductor. It's installed on a small vertical PCB and is covered by insulation tape in order to decrease EMI noise.

    That looks like paper and vinyl / PVC electrical tape wrapped around the vertical PCB, which provides electrical isolation only, I doubt it would make measurable difference in EMI.
  • Aris_Mp
    According to my experience so far they are, unfortunately.

    This provides some EMI protection. There is no need for electrical insulation on this board. As for the degree or EMI protection I can examine this with my EMC probes (once I find the time to do it).
  • Andi lim
    this review said uses a half-bridge topology, I only see one main capacitor. half bridge usualy uses 2 main cap and 2 main switcher right ?
  • Aris_Mp
    the number of APFC caps has nothing to do with the primary topology. However yes half-bridge uses 2 switchers.
  • Andi lim
    You are right, this is half bridge with LLC series resonant converter, nothing wrong with the primary capacitor.