Efficiency is only Bronze, and the maximum operating temperature at which this PSU can deliver its full power continuously is 40°C, while the ATX spec recommends 50°C. The specs on paper won't stop us from testing this unit at up to 45°C, as we do with all PSU samples.
|Enermax ETA550AWT-M Features & Specs|
|Max. DC Output||550W|
|Efficiency||80 PLUS Bronze|
|Operating temperature||0°C - 40°C|
|Protections||Over Voltage Protection|
Under Voltage Protection
Over Current Protection
Over Power Protection
Over Temperature Protection
Short Circuit Protection
|Cooling||120 mm Twister Bearing Fan (ED122512H-DD)|
|Dimensions||150 mm (W) x 86 mm (H) x 140 mm (D)|
|Compliance||ATX12V v2.31, EPS 2.92|
|Price at time of review (exc. VAT)||$109.99|
Every protection feature, including our favorite, OTP (Over Temperature Protection), has been included; it is incredibly important to a PSU. Also, the cooling fan is equipped with twisted bearings in order to last longer and produce less noise than a sleeve- or ball bearings one. Well, we will see about the fan's output noise during our test sessions, since a 120 mm fan in a Bronze PSU with high heat dissipation will have to work extra hard once the ambient climbs above 40°C. A 140 mm fan, which would have been less noisy, apparently couldn't be installed due to unit's restrictive dimensions.
Finally, the two +12V rails and all the other features of the unit compound to meet the most recent ATX spec (v2.31) requirements, and the warranty period should, in our opinion, be longer given its price tag of over $100.
The two +12V rails can almost deliver the full power of the unit by themselves, which is an indication that the minor rails—strong enough for a modern PSU— are generated by DC-DC converters. Finally, the 5VSB rail has the typical maximum current output, and do we really care about the -12V rail nowadays? The rail is a relic of the past, and we expect the next ATX spec to abolish it.
|Enermax ETA550AWT-M Power Specs|
|Total Max. Power||550W (600W Peak for up tp 60 sec)|
Cables & Connectors, Power Distribution
The number of available connectors is adequate for the capacity of the PSU. We should also note that this is the first time that we see a PSU with an odd number of PCIe connectors (three), since most PSUs available on the market are equipped with an even number of such connectors. However, most 500-550 W units only have a couple PCIe connectors, so the inclusion of another is a very welcome feature—in case you want to use a strong VGA as the main workhorse and another low-end graphics card for physics.
|ATX connector (540mm)||20+4 pin|
|4+4 pin EPS12V/ATX12V (610mm)||1|
|6+2 pin PCIe (500mm)||3|
|4 pin Molex (500mm+150mm+150mm+150mm) / FDD(+150mm)||4 / 1|
The length of all cables is adequate, since this unit will most likely be installed into a small- or medium-sized chassis, and the distance amongst connectors, on cables that hold more than one, is good. All connectors also utilize 18AWG sized wires, which is the standard according to the ATX specification.
Enermax was kind enough to provide the rail distribution on the modular chassis. As you can see, almost half of the connectors are powered by 12V1, which leaves the others to the 12V2 rail. The native ATX 24-pin connector is fed by 12V1, and the EPS connector is fed by 12V2, which means that you will mix one PCIe connector with the single EPS connector if you use all PCIe connectors. This is by no means optimal, but the small number of +12V rails also makes such a setup unavoidable.