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Cooler Master MasterWatt Maker 1200 MIJ PSU Review

Protection Features

Check out our PSUs 101 article to learn more about PSU protection features. Our protection features evaluation methodology is described in detail here.

Protection Features
OCP12V: ✗ 5V: 32.25A (129%) 3.3V: 25.82A (103%) 5VSB: 6.9A (197%), 3.3 V
OPP1408.8W (117.4%)
OTP✓ (133°C @ +12V heat sink)
SCP12V: ✓ 5V: ✓ 3.3V: ✓ 5VSB: ✓ -12V: ✓
PWR_OKOperates properly
SIPSurge: MOV Inrush: NTC Thermistor & Bypass Relay

The 5V rail has OCP that's set pretty high, while the opposite is true for the 3.3V rail, given that its official maximum current output is 25A. The 5VSB rail can go sky-high, which we consider to be a problem. With 6.9A, its voltage drops to a worrying 3.3V! Murata's engineers totally missed this, as did Cooler Master's. Careful: the 5VSB circuit can easily be fried if you apply such a high load for a long time.

The OPP limit is set reasonably, given this PSU's capacity. Moreover, the power-good signal is accurate and the inrush current protection does a really good job. For added protection, this PSU is equipped not with one, but three fuses. There's one right after the AC input, one on the 5VSB circuit, and one before the DC-DC converters' PCB.

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