Introduction:
Our first power supply review for Seasonic left an amazing first impression on us. After testing out the S12II we were able to see that their power supplies truly do live up to all the amazing hype they get as being not only ultra-silent but also high build quality and performance levels as well. The only drawback of that power supply? It wasn't modular, and for some users with tightly packed cases, this could pose a problem for airflow. Today we've teamed up with Seasonic again to bring you a review of their M12II power supply - the modular brother to the S12II.

In The Box:
(1) M12II power supply
(1) Bag of modular cables
(1) Power cable
(1) User's Manual
(4) Installation screws
(1) Case badge

 
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Specs:

Features:
Externally, the M12II looks nearly identical to the S12II with the exception of the modular cable design. Because of the modular cables, the casing is a mere 20mm deeper on the M12II. The only cables that are hardwired on the power supply are the ATX 20/24 pin strand, one 4-pin 12V and one 8-pin 12V; the rest of the cables are entirely modular (and all sleeved). All the connections on both M12II models are outlined in the chart below. I must point out that I've always liked the way Seasonic handles the floppy drive connectors. Instead of putting them on a couple of the Molex cable strands, just to get in the way for those who don't use them, they've actually put them on a separate adapter that you can plug into one molex plug and get two floppy drive power connectors.

 
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On the inside, the only major enhancement the M12II brings to the table is a slightly enhanced +12V rail system. The 12V rails have been upped slightly and now provide 420W of output power instead of only 408W in the S12II. I was disappointed to see the lack of solid state capacitors in the M12II. Having solid state capacitors has many pros which were well discussed in the S12II review, and for those looking for the absolute best power supply for their money, that can be a huge selling feature. If Seasonic were to pack solid state capacitors into a modular power supply like the M12II they could really have a beast on their hands. The caps used under the hood of the M12II seem to be all Japanese made which aren't too bad (generally preferred over Chinese made capacitors).

In terms of energy efficiency, the M12II shares the same 80Plus logo as the S12II did. Seasonic claims these units can reach up to 85% efficiency! What does this mean for you? Not only an extremely quiet power supply because it will run cooler, but since your energy is being used more efficiently you could also save slightly on electricity bills if your system is on a lot.

The cooling fan is the same 120mm ADDA that we saw in the past Seasonic review as well. This fan is temperature controlled - meaning it will only spin as fast as required to properly cool the power supply at whatever temperature it's currently operating at. This will help to keep noise levels as low as possible and since it's an 80Plus rated power supply, this means really low! At full speed, this fan is rated at 61CFM. The fan vents out a honeycomb shaped grill in the back of the power supply.

 
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As with the S12II, the M12II also has active power factor correction (Active PFC you may know this term as). This ensures that your computer will get the "cleanest" power possible by helping to reduce line loss and power distortion that may occur on the way into the supply from your wall. In addition to that you also have over power, over voltage and short circuit protection to keep your system safe at all times.

Installation:
Installation of the M12II was a breeze and I did not encounter any problems along the way.

Testing:
The system the M12II will be tested on is listed below.

Testing System:
CPU: AMD Athlon 64 3200+ (Socket 939) @ stock speeds
Motherboard: Biostar NF4UL-A9
Memory: 1gb (4x256mb) PC3200 400mhz
HDD: Western Digital 160gb SATA II (WD1600JS), Seagate 250gb SATA II
Video: Asus EN7600GS Silent
Sound: Mackie Onyx Satellite Firewire Audio Interface
Power Supply: Seasonic M12II 500W
OS: Microsoft Windows XP Professional SP2

To test the M12II I will use the same method I use for all power supply reviews. First, the idle voltages will be taken and then after running the system at 100% load for 30 minutes I will record the load voltages. These results are seen in the graph below:

I was surprised to see that even under such heavy load that my system was only able to give a slight nudge to the +12V rail's voltage. The +5V and +3V voltages were dead on under idle conditions and amazingly were able to maintain that performance even under heavy load for a long period of time. Some people question why Seasonic doesn't make these power supplies in wattages higher than 500W. When it comes down to it, quality is the answer. A "well built" 500W power supply could easily outperform a cheap-o 800W+ power supply on any day. As you saw with my test results, my system wasn't even able to budge the voltages on the M12II, meaning it can still take a heck of a lot more! This is impressive when you compare it to the fact we've reviewed some 800W+ power supplies in the past where my system has been able fluctuate the voltages quite a bit, even on some past 500W model reviews for other manufacturers!

Throughout all my testing of the M12II I was glad to see that it's kept the same noise levels at the S12II - I mean lack-of noise levels! In my system at about 1m away I could not hear the M12II in operation, even when the system was under full load for a while. The only noticeable way to hear the M12II over my other components was to put my ear right up to it and even then the only sound I could hear was the sound of the quiet motor and some airflow. This is truly the signs of a high quality 80Plus power supply in action!

Conclusion:
Seasonic has left me impressed yet again with their M12II power supply. The S12II we reviewed a couple months ago set a very good first impression for this company as well as a high bar for quality. The M12II we reviewed today was able to show us that they aren't slowing down and it's taken that bar and raised it even a little more. Seasonic has shown us that they can make high performing power supplies with the S12II and now the M12II. Amongst taking the time to do this they still haven't lost their attention to quality because both supplies show you the manufacturing quality right from the minute you first see them in the box. I was impressed with the results of testing the M12II; it's proven to have very solid voltages and was able to maintain practically silent operation at the same time. Packing all that together with a modular cable design, this is one excellent power supply that is sure to satisfy the needs of anyone looking for quality - be it gamers, overclockers or home users.

Pros:
Solid performance results
Modular design
Three year warranty
80Plus rating
Ultra-silent operation
Enhanced +12V rail system compared to the S12II (Better for gamers with high end video cards)

Cons:
Lacks the solid state capacitors the S12II has