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Published: November 8, 2006 | Source: Seasonic | Author: James Napier

Seasonic M12 600w Modular PSU

Load Testing

NOTE: The voltage results obtained for the Seasonic M12 unit are deemed to be inaccurate due to a problem discovered with the OC3D testing equipment. The unit is currently in the process of being re-tested.

In order for the results from all current and future PSU reviews to remain fair and comparable, Overclock3D uses a custom built Power Supply load stress tester.

The tester will be placing the following loads on each of the M12’s rails:

+3.3v – 20a Load
+5.0v – 20a Load
+12v1 – 10a Load
+12v2 – 10a Load
+12v3 – 10a Load
+12v4 – 10a Load

The results are collected from a Mastech MAS-345 Multimeter which logs its readings via RS232 to a PC.

Seasonic M12 600w +3.3vSeasonic M12 600w +5.0v

The M12 proved to have very stable voltages on its +3.3 and +5v rails when placed under load. No fluctuation what so ever was exhibited on the +5v rail and a minimal amount of fluctuation (0.02v) was seen on the +3.3v rail.

Seasonic M12 600w +12v1Seasonic M12 600w +12v2

Seasonic M12 600w +12v3Seasonic M12 600w +12v4

All of the +12v rails on the M12 told exactly the same story. No change in Idle and Load voltages was seen, placing this power supply among some of the most stable units we’ve ever tested here at OC3D. I certainly wasn’t expecting these kind of results from the M12 and actually tested the unit several times to ensure that our test equipment wasn’t faulty!

Efficiency Testing

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains against the power (in watts) consumed by the OC3D power supply stress tester. These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.

Seasonic M12 600w Efficiency
The M12 was placed under a load of 646 watts. This counts for a total of 107% of the power supplies rated output. At this load, the power supply required 771 watts from the mains. Therefore the efficiency of this power supply can be found by a simple equation: (646 / 771) * 100, which works out to be an efficiency rating of 83.7%.

Noise Testing

Possibly the hardest part of any PSU review is summarising the level of noise given out by the unit. The threshold for what is considered ‘noisy’ varies from person to person and therefore what I may consider a quiet unit, another person may consider extremely loud. A common way to resolve this issue is to use a dBA meter to measure the units noise level, however this doesn’t take into account the pitch (type) of noise emitted and whether it is likely to irritate end users.

For this reason OC3D records all power supplies at idle and load in wav format for you to make your own informed decisions. All recordings are taken at 30cm away from the PSU and outside of a PC case. You will need to remember that noise levels will be reduced by varying amounts once the PSU has been installed inside your PC enclosure.

Idle Recording – Download
Load Recording – Download

After hearing good things about the Seasonic units with regards to noise levels, I was expecting the M12 to be a very quiet power supply. However, these expectations started to turn into concerns once I had seen the choice of fans used inside the unit. With two fans rated between 32dBA and 39dBA it became hard to see how these could possibly be considered “Super quiet” as stated on the M12’s packaging.

At Idle I started to regain faith in Seasonic’s “super quiet” marketing, with the M12 being almost totally silent due to both fans running at very low RPM.

However, once the M12 was placed under load the fan speed increased significantly, and as you can probably hear from the recordings above – made the unit really quite loud. Personally I would find it very hard to recommend the M12 to anybody seeking a silent PSU for their computer.