Introduction

Today we're reviewing a new power supply from Super Flower, a company that has been producing power supplies predominantly for other companies, though they also sell PSUs under their own brand. Several years back their units were a lot more common and you could find them in online shops around the globe, but their presence has been fading. However, we have reviewed a few other brands that were built by Super Flower. Super Flower was one of the first companies to introduce fans larger than 120mm in power supplies and in fact they have several patents related to this. Besides power supplies the company also offers PC cases.

The Amazon series we are reviewing comes in six different wattages: 550W, 650W, 750W, 850W, 1000W, and 1200W. The specs of the models differ in their maximum combined power and in the potential output on the 12V4 and 12V5 rails on higher spec units. The 550W unit also omits the 12V5 and 12V6 rails.

The label shows a total of six 12V rails which is uncommon for a 650W power supply. Each of the rails is listed as 20A, except rails 12V4 and 12V5 are 30A. However, the total combined power of the 12V rails is only 624W, which you could exceed just by putting a maximum load on the two 30A rails. This raises the question of whether there's any reason to include additional rails, considering users will only be able to use a small fraction of the theoretical maximum load if they connect devices to each rail. This is in direct contrast to other companies that opt to use a single high amperage 12V rail. The 3.3V and 5V rails are in line with what we normally see, with a total combined power of 170W. Super Flower might want to fix the German spelling on the label, since hardly any of the words are spelled correctly. (Ed: The English grammar on the packaging could also use some work.)

Packaging and Appearance

With a name like Amazon, you might think Super Flower would choose to go with a jungle theme on the packaging and marketing material... and you'd be right. This is also a play on the "green" theme, with 80Plus and 80Plus Bronze labels prominently visible on the packaging. The box doesn't feature any noteworthy accessories, at least on our review unit. All you get is the power supply and the manual -- though it's worth noting that the Amazon series isn't available in the market yet, so actual retail models may differ from what we received.

Inside the box we find a black power supply with a large 140mm fan. We received the LED version (much to our disappointment), but other than the lighting we don't expect the fans to differ in speed or acoustics. The back as usual is perforated with the power jack and power switch on one side. Super Flower uses hexagon holes that are larger than what we are used to seeing. All the other sides are closed so that all airflow will exhaust out the rear of the case. The Amazon series does not use any form of cable management, so all of the cables are fixed to the power supply.

Cables and Connectors

All of the cables are sleeved with a black and golden net, similar to Enermax PSUs. The 650W power supply has a nine cable harnesses: two each for SATA and Molex connectors, 24-pin and 4-pin ATX connectors, and an additional 8-pin EPS connector (useful for workstations and some high-end motherboards). The remaining two harnesses are for graphics cards, four PEG connectors -- two 6-pin and two 8-pin (6+2 pins).

The fan is manufactured by Globe Fan, and as you can see it uses a ceramic bearing.

Internals

The internal layout and arrangement of the components looks good. Half of the input filtering stage is on a small sister PCB connected to the AC input, but all of the necessary components are present. The filtering stage continues on the upper part of the PCB and right corner. The rectifier bridge has its own aluminum plate attached that acts as a heatsink. The PFC IC is covered with a yellow foil that we would have had to remove to take a picture, so we left it alone. The main capacitor is from Nippon Chemi-Con, a premium Japanese capacitor manufacturer. It is rated at 470µF and 450V.

The transformer looks like it was handpicked and marked with 85% to provide an extra boost to overall efficiency and power quality. Looking closer, we see that there's quite a bit of extra glue on the various parts; while that shouldn't interfere with performance, it does indicate that this is probably a custom-built preproduction model. The largest coil below the heatsink for example is covered with glue to secure isolating plastic parts around it. The heatsink has many scratches, which is another indication that this sample does not come from a normal product line.

Testing with the Chroma ATE Programmable Load

Our test equipment consists of two Chroma programmable DC Loads that enable us to test power supplies with an output of up to 1500W. The biggest advantage of the Chroma DC Loads is simply the high precision it provides. It can measure differences as small as 0.001V and 0.0001A, which will provide us with best-in-class results.

When programming the Chroma with specific amounts of load calculated according to the ATX norm, we are able to load power supplies to an exact percentage. We can now show results at every specific percentage needed. To get the best overview of a power supply, we load each unit with 10%, 20%, 50%, 80%, 100%, and 110% of the specified output. This is easy to calculate for a 1000W power supply: the 10% load is 100W and 110% load is 1100W. Remember that this is the amount of power the PSU delivers; due to inefficiencies, a power supply will actually draw more power from the wall.

Note: If you would like to know more about our testing methodology, equipment, and environment, please read our PSU testing overview.

We have added an additional 10% on the highest load to see how the units perform with overload. This test will be performed in all future reviews. The overload test is performed at room temperature as well as under more stressful conditions; to ensure we are not too cruel to the power supplies, we will keep the ambient temperature at 50°C in the stress test. Experience shows that many units can stand the overload at room temperature but will experience problems with higher temperature and overload together. Only the best-built units will survive this.

The Testing Environment

There is one flaw in testing power supplies with programmable loads while trying to measure the sound pressure levels at the same time. Because the programmable loads get very loud, there is no chance of hearing the power supply on the test stand. In order to make accurate measurements of the noise levels we needed a way to separate the test unit and the programmable loads. Our solution was to build a very thick box around the unit.

We concluded that a five-layer box with a total thickness of 6" (15cm) containing two layers of wood and three layers of special foam would suffice. It is designed as a box within a box. The inner box does not touch any part of the outer box, making it difficult for acoustic noise to pass through in the form of vibration. Each box is isolated on both sides with a layer of heavy foam that is normally used to insulate engines. On the inside we have an additional layer of 4" (10cm) thick pyramidal foam on every side of the box to eliminate the acoustic waves coming from the test object as well as we can.

To ensure a completely closed system we installed the printed circuit board that the connectors of the power supply are attached to inside the anechoic room/box. In other box designs, you would need to put all the cables through the wall. Unfortunately, that would result in the inside of the box not being fully isolated anymore. Our design keeps everything that needs to be connected inside of the box and maintains isolation.

DC Output Stability and Quality

During testing, we found the voltage regulation acting on the 5V and 3.3V rails rather strange; normally, these two rails look very similar, which is clearly not the case here. The 3.3V rail even increases the output voltage with increasing loads, starting at 3.40V and rising up to 3.46V (which is very close to going out of spec). In contrast, the 5V rail shows a large decrease, dropping to 4.86V with 110% load. Most of the six 12V rails stay above 12.00V during testing, though some drop below once we reach 80% load.

Efficiency and PFC

Super Flower claims this is a high efficiency power supply, and indeed we see up to 87% with 230VAC input. The curve is typical of most power supplies, starting low and reaching its peak at around 50% load. Maximum efficiency regardless of input is at around 300W, and depending on input voltage you will want a minimum load of 100W to 125W in order to stay above 80% efficiency. 80Plus Bronze certification requires a minimum efficiency of 82% at 20% and 100% load, and 85% efficiency at 50% load; the Super Flower Amazon 650W does meet those requirements, but only with 230VAC; 120VAC appears to barely miss the mark, although we're probably splitting hairs.

The power factor correction is one of the best we have seen in recent time. With lower input voltages, you will have an almost constant PFC of more than .99.

Temperatures, Fan Speed, and Acoustics

Both heatsinks remain very cool relative to what we normally see. During testing they stay under 50°C and only surpass that temperature when we exceed the maximum 650W power rating. The heatsink and exhaust temperatures are very close, which shows that the power supply is doing a good job of getting rid of excess heat. The Super Flower 650W achieves one of the best temperature results we've seen to date, likely helped by the 140mm fan.

The fan speed remains at its minimum 600 RPM up until 80% load. With a large fan size and good heatsinks, temperatures are low enough that the fan simply doesn't need to spin any faster. At maximum load and with a warmer ambient temperature the fan begins turning faster, but it still doesn't reach very high RPMs. A quick calculation of fan area indicates the 140mm fan should move at least 36% more air than a 120mm fan, so even though the fan speed is much slower than what we normally see it should be sufficient.

A major advantage of having a large fan spinning at lower RPMs is reduced noise levels, which we see in the above graph. In fact, outside of fanless power supplies, this is the quietest power supply we have ever heard -- or not heard in this case. It stays at an incredible 18dB(A) up to 550W, at which point additional loads increase the noise level by 1dB(A). The fan makes no noise that we could detect, and there wasn't any ticking (something we've noticed with some other low RPM fans). Whatever else we might say, the 140mm fan with ceramic bearings certainly impresses.

Conclusion

From what we saw during testing, the Super Flower Amazon PSU appears to be a very good product. Of course, since this looks like a preproduction unit we can't say for sure how it will compare with actual retail models made on the standard factory lines. Super Flower says the unit we received should be representative of stock units, and if so that's great; we will make sure to get our hands on a retail unit for comparison once they begin shipping.

In terms of feature set, there's nothing truly remarkable with the Amazon series. It's a typical power supply with no funny gimmicks; the only really noteworthy feature is the 140mm fan. It provides very good voltage distribution, good efficiency, and very silent operation. The build quality is very good as well, even though we don't like to see large amounts of glue all over the place. The length of the housing might be a little long for a 650W power supply, but that's because Super Flower uses the same topology for all of the power supplies in this series. They selected high-quality components, and the result is a very good power supply. The number of connectors is good for a 650W unit, allowing users to power up to two of the most powerful GPUs currently on the market. Cable lengths are also decent, with 50cm ATX connectors and PEG connectors at 50cm and 65cm.

The overall performance is very good, surpassing much of the competition that has been around for a while. Voltage regulation was good on the six important 12V rails. The 3.3V provides a constant high voltage of up to 3.47V while the 5V rail is almost the opposite with somewhat low results under higher loads. The efficiency reaches up to 87% with 230VAC and up to 85% with 120VAC.

The temperatures inside of the power supply were very low, reaching only 50°C with normal ambient room temperature. The fan spins at a very sedate 600RPM most of the time, and only starts turning faster at more than 80% load. The temperature does begin to rise at higher loads, and it would have been nice if Super Flower allowed the fan to spin a bit faster at maximum load -- obviously there's still plenty of room left in terms of noise output. As it stands, the Amazon 650W only puts out an exceptional 18dB(A) at up to 550W, making this the quietest actively cooled power supply we have seen to date. If you are like most users and you have a PC that never requires more than 500W, you will never hear this PSU.

The only real question we have is pricing. We will have to wait until Super Flower begins shipping these units to get a price quote.