Seasonic M12II-430 modular cable PSU

Seasonic’s original M12 was an excellent power supply marred by a small 60mm fan that didn’t turn off once it started spinning. The M12-II is a lower power line that is modular that does away with the 60mm fan. Is it better than the original? By SPCR standards, yes.

February 13, 2008 by Devon Cooke

Product	Seasonic M12II-430 430W ATX12V 80-Plus Power Supply
Manufacturer	Seasonic
Market Price	US$110~150

Like movies, most pieces of computer hardware are better off without sequels.
Good hardware tends to stand on its own, accepting minor tweaks and revisions,
while bad hardware tends to get renamed and recreated. Seasonic’s M12 power
supplies, however, may just warrant the "II" tagged on to the end
of their new revision.

As the new name indicates, the M12-II is a significant revision of the
original M12 line, and, for now at least, the two lines will coexist. The
"II" designation matches the "II" in the
recently reviewed S12-II, and the two models share Seasonic’s latest circuit
design. As before, the "M" designates modular cables, but the M12-II
gets rid of the extra 60mm cooling fan and reduces the capacity points to more
realistic 430W and 500W models. As a result, the pricing for the M12-II is more
mainstream than before; no longer is the M12 a top-end-only product.

Comes in 430W and 500W models.

These new models will be welcomed by those who respect Seasonic’s reputation
for quality and low noise but were unwilling to pay upwards of US$150 for modular
cables. At the time of writing, the 430W model is priced starting at US$110,
but this should come down as retail availability improves.

FEATURE HIGHLIGHTS

Seasonic M12II-430 Feature Highlights (from Seasonic web site)
FEATURE & BRIEF	COMMENT
Sufficient +12V Support Enhanced +12V current capability broadens utilization possibilities.	+12V is really the only important voltage line these days.
Super High Efficiency [up to 85%] Optimal solution for low energy consumption, noise & heat.	We expect nothing less from Seasonic.
Active Power Factor Correction [99% PF] Reduces line loss & power distortion.	Reduces the current draw, which means less likelihood of tripping your circuit breaker.
High Reliable Aluminum Electrolytic Capacitors Top quality components increase product life & reliability	A quality-control choice in response to issues with bad capacitors in many home electronics.
Detachable Modular Cable Use precisely the cables you need, enhance system airflow and minimize clutter.	A value-added feature that allows Seasonic to justify the high cost of the M12-II
Double Forward Converter Circuit Design Advanced topology for the highest efficiency.	An advanced circuit that has helped Seasonic build their reputation for quality and efficiency.
Double 12cm Ball Bearing Cooling Fan Increases airflow & lifetime and reduces rotation speed and noise.	Perhaps this should read "12cm Double Ball Bearing Fan"? Whatever it means, there is only one fan…
Smart & Silent Fan Control [ S²FC] Smart thermal control to balance noise & cooling.	Seasonic’s usual quiet fan control circuit.
Soft-Mounting Rubber Cushions Reduces fan rotation & vibration noise.	We can’t complain about noise reduction!
Ultra Ventilation [Honey Comb Structure] Minimized airflow resistance for maximum cooling.	Good ventilation is key for quiet performance.
All in One DC Cabling Design Supports PC, IPC, workstation, server, & dual CPU systems.	Includes an 8-pin EPS12V CPU connector for dual CPU systems.
Universal Video Card Support Support new PCI-E video card technologies	Two PCIe connectors for SLI / CrossFire.
Universal AC Input [Full Range] Plug & run safely anywhere in the world.	Ok.
Patented Easy Swap Connector Unplug the connectors easily & quickly.	Quickly becoming redundant as IDE connectors fade from use.
5 Year Warranty Our Commitments to superior quality.	A better warranty than most hardware…

SPECIFICATIONS

OUTPUT SPECIFICATIONS: Seasonic M12II-430
AC Input	100~240Vac; 50/60 Hz
DC Output	+3.3V	+5V	+12V1	+12V2	-12V	+5VSB
Maximum Output Current	20A	20A	17A	17A	0.8A	2.5A
	130W		360W
Maximum Combined Power	430W
Operating temperature: 0 to 50°C. Relative Humidity: 20% to 80%. (The rated power will reduce from 100% to 80% from 40°C to 50°C)

EXTERNAL TOUR

The M12-II retains the matte black paint job of the original M12 line and looks
very similar. A few details have changed: The 60mm fan is gone, of course, as
are all other vents. The main fan vent on the bottom is the only place for air
to get in, and the back panel is the only exhaust. A couple aesthetic changes
have been made: There is now a blue Seasonic badge over the fan hub on the bottom,
and the specification label has been redesigned in orange and black. These are
small touches, but they leave an impression of attention to detail and quality
— a marketing trick to be sure, but one that will be appreciated by the
image-conscious builders who make up the M12-II’s target market.

Like the original M12 (and most other modular power supplies), the M12-II is
slightly longer than a standard power supply to make room for the plugs on the
inner panel. It’s 160mm long rather than 140mm — not a big difference,
but something to consider in the confines of a tight case.

No supplementary air vents — a change from previous Seasonics.

Seasonic has used the space freed up by eliminating the rear fan to space out
the sockets for the detachable cables a bit. They are now arranged in a neat
row along the bottom edge of the back panel, where they are easy to access even
when installed in a system. This is an improvement: The original M12 wedged
all the connectors against the far wall of the case.

A splash of blue over the fan hub gives the M12-II a high-end appearance.

The usual open hex venting.

CABLES AND CONNECTORS

There are seven detachable cable sets, plus a floppy adapter and the main ATX
and AUX cables, which are permanently attached. All cables are sleeved in black
plastic mesh, and the IDE connectors have grips that make them easy to remove.

• 20″ permanently attached cable for main 20+4-pin ATX connector
• 20″ permanently attached cable for 4-pin AUX12V connector
• 20" permanently attached cable for 8-pin AUX12V connector
• 2 x 30″ detachable cables with three SATA drive connectors
• 3 x 27″ detachable cables with two 4-pin IDE drive connectors
• 2 x 21" detachable cables with two 6-pin PCIe graphics connectors
• 1 x 6" splitter from one 4-pin IDE connector to two floppy connectors

There is no possibility of plugging the cables sets in the wrong way; the PCIe
and the drive cable sets use completely different connectors. IDE and SATA cables
share the same type of connector, but are wired so that they are compatible
with the same ports on the power supply. Any well-designed modular cables should
be this way, but it’s surprising the number of power supplies we’ve seen that
allow serious electrical faults because the connections aren’t clear.

The 430W model comes standard with two 6-pin PCIe connectors for SLI or Crossfire
configurations (it’s officially Crossfire certified). The new 8-pin connectors
are not supplied. Seasonic does list one 8-pin connector for the 500W model,
but the 500W sample we looked at did not include one.

INTERIOR

Seasonic has changed the internal circuit design for their II-series S12s and
M12s. It’s not clear what changes have been made — it’s still a dual forward
converter design — but a few changes to circuit topography are evident.
Ultimately, we’re not terribly interested in the technical nitty-gritty so long
as it performs well — and if the
S12-II is any indication, it will.

Greatly reduced heatsinks make for a much more open design.

The most obvious change is the size of the heatsinks: They’ve shrunk and they’re
painted black. Seasonic’s characteristic block-toothed design has been scaled
back so that the "teeth" are now short and stubby, leaving the circuit
board underneath much more open to the direct airflow from the fan. A third
heatsink has been added, which should mean that the main heat sources (typically
diodes) are now spread out more diffusely.

The heatsinks have short, stubby teeth.

The other change we noticed was the thermal ratings on the capacitors. Seasonic
has always paid attention to capacitor quality; they’ve been using Japanese
capacitors for a while, and the M12-II is no different. What’s changed is the
capacitor grade: all capacitors are now rated for 105°C rather than the
standard 85°C. Is this necessary? Probably not, but it helps with peace
of mind, and that’s important if you’re paying top dollar for a power supply.

105°C input capacitor…

…and 105°C output capacitors.

FAN

The fan is nothing we haven’t seen before: It’s the usual medium-speed Adda
model that’s been used in Seasonic models (and many other power supplies) for
years. These ball bearing fans are durable and heat-resistant, but sound surprisingly
smooth at low speeds.

A clear plastic baffle helps direct airflow.

What’s new is a clear plastic baffle that blocks about a quarter of the fan’s
area. It’s designed to shield off the area near the exhaust vent, creating a
low pressure zone by the vent that draws air from the far reaches of the power
supply. This is an improvement; it will mean better airflow across all components
and less "short-circuited" air that flows directly from the fan out
of the exhaust vent.

TESTING

For a fuller understanding of ATX power supplies, please read
the reference article Power
Supply Fundamentals & Recommended Units.
Those who seek source materials can find Intel’s various PSU design
guides at Form Factors.

For a complete rundown of testing equipment and procedures,
please refer to SPCR’s PSU Test Platform V.4.
The testing system is a close simulation of a moderate airflow
mid-tower PC optimized for low noise.

In the test rig, the ambient temperature of the PSU varies
proportionately with its output load, which is exactly the way it is in
a real PC environment. But there is the added benefit of a high power
load tester which allows incremental load testing all the way to full
power for any non-industrial PC power supply. Both fan noise and
voltage are measured at various standard loads. It is, in general, a
very demanding test, as the operating ambient temperature of the PSU
often reaches >40°C at full power. This is
impossible to achieve with an open test bench setup.

The 120mm fan responsible for “case airflow” is deliberately
run at a steady low level (~6-7V) when the system is run at “low”
loads. When the test loads become greater, the 120mm fan is turned up
to a higher speed, but one that doesn’t affect the noise level of the
overall system. Anyone who is running a system that draws 400W or more
would definitely want more than 20CFM of airflow through their case,
and at this point, the noise level of the exhaust fan is typically not
the greatest concern.

Great effort has been made to devise as realistic
an operating environment for the PSU as possible, but the thermal and
noise results obtained here still cannot be considered absolute. There
are too many variables in PCs and too many possible combinations of
components for any single test environment to provide infallible
results. And there is always the bugaboo of sample variance. These
results are akin to a resume, a few detailed photographs, and some
short sound bites of someone you’ve never met. You’ll probably get a
pretty good overall representation, but it is not quite the same as an
extended meeting in person.

SPCR’s
high fidelity sound recording system was used to
create MP3 sound files of this PSU. As with the setup for recording
fans, the position of the mic was 3″ from the exhaust vent at a 45°
angle, outside the airflow turbulence area. The photo below shows the
setup (a different PSU is being recorded). All other noise sources in
the room were turned off while making the sound recordings.

INTERPRETING TEMPERATURE DATA

It important to keep in mind that fan speed varies with temperature,
not output load. A power supply generates more heat as output
increases, but is not the only the only factor that affects fan speed.
Ambient temperature and case airflow have almost as much effect. Our
test rig represents a challenging thermal situation for a power supply:
A large portion of the heat generated inside the case must be exhausted
through the power supply, which causes a corresponding increase in fan
speed.

When examining thermal data, the most important indicator of
cooling efficiency is the difference
between intake and exhaust. Because the heat generated in the PSU
loader by the output of the PSU is always the same for a given power
level, the intake temperature should be roughly the same between
different tests. The only external variable is the ambient room
temperature. The temperature of the exhaust air from the PSU is
affected by several factors:

• Intake temperature (determined by ambient temperature and
  power output level)
• Efficiency of the PSU (how much heat it generates while
  producing the required output)
• The effectiveness of the PSU’s cooling system, which is
  comprised of:
  • Overall mechanical and airflow design
  • Size, shape and overall surface area of heatsinks
  • Fan(s) and fan speed control circuit

The thermal rise in the power supply is really the only indicator
we have about all of the above. This is why the intake temperature is important:
It represents the ambient temperature around the power supply itself. Subtracting
the intake temperature from the exhaust temperature gives a reasonable gauge
of the effectiveness of the power supply’s cooling system. This is the only
temperature number that is comparable between different reviews, as it is unaffected
by the ambient temperature.

TEST RESULTS

Ambient conditions during testing were 21°C and 20 dBA. AC input was 121V,
60Hz.

DC Output Voltage (V) + Current (A)

Total DC Output

AC Input

Calculated Efficiency

OTHER DATA SUMMARY: Seasonic M12II-430
DC Output (W)	20.0	42.6	64.2	91.0	150.0	201.0	252.2	299.6	429.4
Intake Temp (°C)	20	20	21	22	26	24	26	28	29
Exhaust Temp (°C)	24	26	27	30	36	40	40	41	46
Temp Rise (°C)	4	6	6	8	10	16	14	13	17
Fan Voltage (V)	4.1	4.1	4.1	4.1	4.1	4.6	6.1	8.1	11.1
SPL ([email protected])	21	21	21	21	21	24	28	35	41
Power Factor	0.93	0.97	0.98	0.99	1.00	0.98	0.99	0.99	1.00
AC Power in Standby: 1.3W / 0.28 PF AC Power with No Load, PSU power On: 6.7W / 0.77 PF
NOTE: The ambient room temperature during testing can vary a few degrees from review to review. Please take this into account when comparing PSU test data.

ANALYSIS

1. EFFICIENCY

The M12-II is 80-Plus certified,
so we already know it’s efficient. Our test sample reached its peak of almost
85% around 200~250W — right where a high end system is likely draw it’s
peak power consumption. At the lower end, it hit 66% at 20W and 75% at 40W,
which are excellent results. Bear in mind that most systems spend most of
their time idling within this range.

All these results are are within a percent or two of the
results we got for S12II-380. There’s little doubt the two models are
based off the same circuit, though the S12II-380 had a slightly tweaked efficiency

curve appropriate to it’s lower capacity.

2. VOLTAGE REGULATION was excellent under ordinary test conditions,
staying within ±3% though all the normal tests. The crossload test
stressed things a little more, pushing the +12V line to as low as 11.56V,
but this is well above the minimum acceptable voltage of 11.40V. The crossload
test is tougher than any realistic load, and it’s unlikely the lines will
ever be stressed like this in real usage.

3. RIPPLE was higher than the recently reviewed S12II-380, but still well within the ATX12V specification, and modest compared to most tested power supplies.

4. POWER FACTOR was close to perfect across all loads, as is the norm
for most power supplies with active correction circuitry. It wasn’t quite
perfect at the very low end, with a ratio of 0.93 at 20W, but this is a lower
load than the M12-II will ever realistically face.

5. LOW LOAD TESTING revealed no problems starting at low loads, and power
consumption with no load was stellar at 6.7W.

6. TEMPERATURE & COOLING

It’s difficult to know exactly what to think of the cooling system in the
M12-II. As noted, the cooling system in Seasonic’s "II" series power
supplies has been heavily tweaked, and there is now much more space for air
flow freely through the power supply.

The thermal measurements didn’t reveal much — results were in line with
most other power supplies we’ve tested. However, there was a bit of an anomaly
just as the fan began to speed up at ~200W: Here, the intake temperature dropped
slightly as the increased fan speed suddenly began to pump hot air out of
the test box at a faster rate. As a result, the thermal difference between
intake and exhaust jumped suddenly and then decreased at the next point
of measurement. It’s not clear whether this anomaly can be attributed to the
better airflow through the M12-II or not. In any case, there’s little question this PSU can keep itself cool.

7. FAN, FAN CONTROLLER and NOISE

The fan controller started just below 4V, and climbed up to stabilize at
4.1V. This is normal behavior for Seasonics. The noise level at 4.1V was residual,
measuring just barely above ambient. Qualitatively, the noise was a very low, smooth
hum.

The fan controller began to increase at the 200W mark — a little lower
than we would like, and earlier than Seasonic’s other recent models, including
the S12-II. Above 200W, the noise was beginning to become intrusive, and by 250W,
it was definitely too loud. The fan controller seemed to react more quickly than usual for a Seasonic
to changes in load, and the changes in fan speed were audible. However,
once the controller picked its level, it stayed at a more or less constant
voltage without audible wavering. The steeper noise to temperature (or load) curve could be due in part to the higher air turbulence noise that quarter-area plastic baffle over the fan must create at higher velocity.

MP3 SOUND RECORDINGS

Each of these recording start with 6~10 seconds of silence to
let you hear the ambient sound of the room, followed by 10 seconds of
the product’s noise.

• Seasonic M12II-430 at 20~150W output, 21 [email protected]: One meter
• Seasonic M12II-430 at 200W output, 24 [email protected]: One meter
• Seasonic M12II-430 at 250W output, 21 [email protected]: One meter

Sound Recordings of PSU Comparatives

• Seasonic Eco Power 300 at 20~90W output, 23 [email protected]: One meter
• Seasonic S12II-380 at up to ~200W output, 21 [email protected]: One
  meter
• Seasonic M12-700 at up to ~250W output, 21 [email protected]: One
  meter
• Corsair VX450W at up to ~250W output, 22 [email protected]: One
  meter
• Sparkle Power SPI220LE at 65W output, 21 [email protected]: One meter

CONCLUSIONS

The M12-II is a different beast from the original M12. The M12-II fixes the main problem with the original version: It no longer has a second
fan to create extra noise and it doesn’t dump waste heat back into the system.
It’s still modular, and it is available at prices and capacities that make sense for most mainstream / quiet PC systems.

It is no longer the high-end luxury piece that the M12 was. The model range of just two models at 430W and 500W is surprising, and the power ratings quite modest for today’s DIY market. It’s nice that the fan isn’t nailed to the floor
by its controller until 300W output. It is an excellent choice (one of many) for a midrange modular power supply, and it’s sure to be quiet under most circumstances. It will probably ramp up a bit under high load in a system with a powerful video card, multiple hard drives and perhaps a hot quad-core CPU.

For best results, the M12-II should be used in systems that consume 200W or
less. It’s quiet at these levels, the electronics are excellent quality, and
it has modular cables. But, let’s face it, these days, it’s actually easier to build a system that stays under 200W than one that exceeds 200W. Whether by coincidence or intelligent design, this happens to be the power level where the 85% efficiency peak is reached as well.

All in all, the M12-II is a solid addition to Seasonic’s lineup, even though it doesn’t really break new ground. Because of Seasonic’s pedigree, it’s quiet and efficient — and it brings modular cables to a reasonable power point. Still, it has lived up to type: The M12-II feels exactly like a sequel. In this case, it’s not a bad thing. There are many quiet PC enthusiast who will find the M12II fits their needs perfectly.

Much thanks to Seasonic
USA for this review sample.

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SPCR Articles of Related Interest:
Power Supply Fundamentals
Recommended Power Supplies
Power Distribution within Six PCs
SPCR PSU Test Rig V.4
Seasonic S12II-380 Power Supply
Seasonic Goes High End Gaming with the M12
Corsair HX520W & HX620W Modular Power Supplies

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