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Cooler Master MasterWatt 550W Power Supply Review

Author: Lee Garbutt
Manufacturer: Cooler Master

A Detailed Look

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The Cooler Master MasterWatt 550W power supply enclosure is painted matte black and measures 140mm (5.5”) deep. The back panel includes an AC receptacle and main power On-Off switch. The PSU features semi-fanless operation, which keeps the fan from spinning when the output power is below 15%.

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The Cooler Master Silencio fan (DF1202512RFLN) is rated for 0.16A and 2500 rpm at 12 VDC. The fan incorporates a Loop Dynamic Bearing (LDB) for long life and quiet operation. This appears to be another variant of a Fluid Dynamic sleeve bearing.

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The front panel on the MasterWatt 550W PSU incorporates three modular cable connectors for the three modular peripheral cables.

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The three modular cables are flat ribbon-style for easy cable routing.

Under the Hood

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Here are a few pictures showing the layout and components inside the MasterWatt 550W Bronze power supply. Cooler Master appears to be using the HEC Group as the OEM for the MasterWatt series.

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The PSU incorporates DC-to-DC converters to generate the +3.3V and +5V outputs from the +12V supply.  The layout of components and the soldering appears to be good. The capacitors are primarily made by Teapo. For example, the primary bulk capacitor is made by Teapo and is rated for 330uf, 400V and 85°C.

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December 3, 2017 | 10:17 PM - Posted by Pink Gnome (not verified)

Surprisingly good for the price. Is there really any practical difference in functionality of any system components between this powersupply and, say, seasonic platinum 550 watt?

December 4, 2017 | 12:22 PM - Posted by Lee Garbutt

Good question. The practical functionality is similar (they both convert AC mains power to the DC voltages required for a PC to operate) but how they do it, how well they do it, and potentially for how long they  keep doing may be quite different. The MasterWatt PSU is a mainstream PSU targeted towards the mass market/average user while the Seasonic Platinum PSU is targeted towards PC enthusiasts looking for a premium PSU.

Compared to the MasterWatt, a Seasonic Platinum PSU uses a more sophisticated design, more components, higher quality components, and includes a longer warranty. These differences result in higher efficiency, better voltage regulation, and reduced AC ripple and noise on the DC outputs, which can potentially make your system more stable and live longer.

December 4, 2017 | 09:11 PM - Posted by Pink Gnome (not verified)

Thanks for the detailed answer!

December 4, 2017 | 01:13 AM - Posted by Cyric (not verified)

I would like to know the OEM for this supply. Coolermaster has a history of using seasonic as an oem which is a good thing.

December 4, 2017 | 12:25 PM - Posted by Lee Garbutt

No, the MasterWatt 550W is not made by Seasonic. Cooler Master appears to be using HEC (based in Taiwan) as the OEM for the MasterWatt series.

December 21, 2017 | 01:43 AM - Posted by Tech We Love (not verified)

Could you test room temperatures at the different watt % usages ? I would like to know how much the room temp rises at each level of power usage.

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