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Modu82+ 625 Power Supply: Enermax to the Forefront

March 02, 2008 by Mike Chin

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Product
Enermax Modu82+ 625W (EMD525AWT)

ATX12V 80-Plus Power Supply
Manufacturer
Enermax
MSRP
US$166

Enermax is a pioneer in retail packaged computer power supplies for the do-it-yourself market. Back in the late 80s, Enermax was the first to apply a metallic paint job instead of the ubquitous grey, the first to create a full-color box to compete for your attention on retail shelves, and the first to employ the then-revolutionary concept of dual fans, sleeved cables, and gold-color wire fan guards.

In more recent history, Enermax has been somewhat swamped by the thundering herd of brands stomping into the retail PSU market. As far as we know, Enermax is the manufacturer of its own power supplies, unlike many of the new brands that are offering PSUs. (We're quite sure that Enermax-branded cases, fans and other non-PSU items are not made by Enermax, however.) Look back at SPCR articles, and you'll see that one of the very first pieces was about modifying an Enermax PSU to make it run more quietly. Their mark on the "silent PC" sector has not been deep or broad thus far; various models over the years have been judged mostly to be good performers, pretty good for noise, but nowhere near the top ranks for quiet. This was our assessment on the most recent midpower models we reviewed, the Liberty 500W and 620W. Enermax also makes 1KW models for OC gamers. (Obsessive-Compulsive and probably Over-Clocking, too)

Recently, our PR contact at Enermax offered us an opportunity to review a first-production sample of a new model that will be hitting all the stores in early March. They have been quietly available for sale in limited numbers for a few weeks, at NewEgg.com, Micro Center, PC Club and ASI Corp. The Modu82+ is a line that Enermax believes will warm SPCR's cockles, and tickle your fancy, dear SPCR readers: It's said to be among the quietest and the most efficient in the world. Since low noise and high efficiency are the qualities that we value most in a power supply, we were eager to accept the Modu82+ 625W for review.

As is common with many early production samples, this one came in a non-descript box. Rest assured that the retail packaging will be as colorful as any Enermax has produced in the past.



The contents of the Modu82+ 625W package.

A foldable fabric pouch filled with sleeved cables makes it clear that the Modu82+ is a modular cable power supply. The new model has many other features, which are summarized below. There are three models in the line, the 625W, a 525W and a 425W. The suggested retail prices of the three models are $165.99, $145.99 and $109.99, respectively. They are definitely not in the budget category, falling in line with the pricing of premium brands such as Seasonic, Corsair and PC Power & Cooling.

FEATURE HIGHLIGHTS

The name of the new series appears to be referenced to a new 80 Plus category. The 80 Plus program, which encourages power supply makers to offer higher efficiency to reduce electricity consumption (on behalf of US public ultilities), has added three new categories of efficiency performance. The original 80 Plus program calls for a power supply to reach 80% efficiency or better at 20%, 50% and 100% of rated power. The new categories call for higher efficiency; please see the details on this page at the 80 Plus site. One of these categories calls for 82% efficiency at 20% and 100% of rated power, and 85% efficiency at 50% of rated power. Hence the 82+ in the product series name.

Interestingly, no test and verification report on this or any other Modu82+ PSU is currently posted at the 80 Plus web site; however, Enermax did send copies of official 80 Plus test reports on the Modu82+ 525W and another model, the Pro82+ 525W. Both met the new "82 Plus" efficiency requirements. The Pro82+ 525W appears to employ the same circuitry and parts as the Modu82+ series, but it is not modular (non-detachable cables) and it is priced $10 lower.

cellspacing="1" width="500">
Modu82+ 625 Feature Highlights (from href="http://www.enermax.com.tw/english/product_supply.asp?listp=68"
target="_blank">Enermax web site)
FEATURE & BRIEF COMMENT
ATX12V v2.3 ready!

Compliant with the newest standard for desktop power supplies.
Hmmm! The ATX12V spec slipped quietly to a new version without our notice.
82PLUS ready!

82-88% efficiency @ 20-100% load. Compliant with ENERGY STAR® 4.0, Blue Angel and 80 PLUS® efficiency requirements.
Impressive claim. See main body text above. FUTURE ready!

12Pin modular design for possibly upcoming new CPU`s and graphics 10 and/or 12Pin connectors. Seems good. 24/7 @ 40°C ready!

Non-Stop industrial class performance at 40°C/104°F ambient. 40°C is good but some PSUs are rated for operation at 50°C.
DXX ready!

For PCI Express 2.0 / DXX next generation graphic cards with 6+2P (8P) PCI-E connectors.
Not that unusual among premium brands.
GAMING ready!

ATX12V v2.3 support for latest Intel Core 2 Duo/Quad/Extreme, and AMD Athlon64X2/X4 & Phenom and SLI or CrossFire X.
That covers every CPU and GPU technology out there today.
WORLD ready!

100-240VAC in with automatic adjustment and active PFC for global usage.
That's a new way of stating a feature that's been around for a while. EMC ready!

Full-scale electromagnetic filtering protects your system against radiation interferences. (CE EMC EN61204-3 compliance) Again, not unusual. AirGuard

Patented air-inlet with optimal aero-dynamical design reducing noisy air turbulences. An interesting feature we'll examine. SpeedGuard

Advanced fuzzy logic 12cm fan speed control for optimal cooling and minimum noise. (Patented) Fuzzy logic? It's used for better elevator control, but how does it work here?
SafeGuard

Industry-leading sixtuple protection circuitry of OCP, OVP, UVP, OPP, OTP & SCP protects your system.
Very good.
TRIPLE 12V rails

The best rail design for this PSU class for maximum safety and compatibility.
Hmmm. Does that mean three current limited runs of cables? Which ones are bundled together? 3 Year Limited Warranty
Fairly generous.

SPECIFICATIONS

cellspacing="1" width="500">
OUTPUT SPECIFICATIONS: Enermax Modu82+ 625
AC Input
100~240VAC, 9.5-4A, 50-60 Hz
DC Output
+3.3V
+5V
+12V1
+12V2
+12V3
-12V
+5VSB
Maximum

Output Current
24A
24A
25A
25A
25A
7.2W
15W
140W 600W (50A) width="200">
Maximum

Combined
height="7">
625W
Presumed rated for full power at up to 40°C.



EXTERNAL TOUR

The showy appearance of earlier Enermax PSUs has been subtly muted here, in a combination of metallic dark grey paint and bold lettering.



Somewhat more subtle appearance compared to Enermax PSUs of yesteryear.



The side lettering gives it a bold look.

The main fan vent on the bottom is the only place for air
to get in, and the back panel is the only exhaust. The exhaust vent is pretty standard: A nicely open pattern of hex holes. There is a power switch next to the AC connector. There is a decorative yellow (gold?) badge over the fan hub,
and the inlet for the fan is contoured or bevelled to present a smoother, more streamlined path for airflow. This is what Enermax describes as the Air Guard. It's quite possible that this feature could reduce air turbulence noise, but probably only at high fan speeds.



Air Guard is the contouring of the fan inlet perimeter.

The output jacks are neatly lined up on the back panel. The five-pin jacks are for the SATA and PATA drive connectors; the 12-pin red ones are for PCIe 12V power.



Neat rear panel appearance with modular cables.



Here's the label.

Four cables are permanently attached, with connectors as shown below: The main 24-pin ATX, a 3-pin (2-wire) fan RPM monitor, 8-pin AUX12V, and standard 4-pin AUX12V.



Four cables are permanently connected.

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.

  • 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
  • 18" permanently attached cable for 3-pin connector for RPM monitoring of PSU fan
  • 3 x 25" detachable cables with three SATA drive connectors
  • 1 x 25" detachable cable with three 4-pin IDE drive connectors
  • 1 x 30" detachable cable with three 4-pin IDE drive and one floppy drive connector
  • 2 x 18" detachable cables with two 6/8-pin PCIe graphics connectors (allows triple graphics cards w/ DX10 and PCIe 2.0)

There is no possibility of plugging the cables sets in the wrong way, as the connectors themselves are shaped so that the male and female ends can only fit in one way, and the PCIe
and the drive cable sets use 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.

The 525W model comes standard with one detachable cable with two 6/8-pin PCIe graphics connectors, as well as a detachable cable with one 6/8-pin PCIe graphics connector for SLI or Crossfire
configurations. It also comes with one less SATA cable.

The 425W model comes a 20+4 main ATX connector, a 4+4 AUX12V connector, just one 3-SATA connector detachable cable, and one detachable cable with two 6/8-pin PCIe graphics connectors.

INTERIOR

Opening up the PSU reveals a tidy PCB with smallish heatsinks that look similar to the ones on the first Enermax PSU I took apart a decade ago. If it works, don't fix it, right?



Nice clean layout suggests good airflow to all the parts.

There are two large 200uF main filter capacitors, each rated at 400V and the
standard 85°C. In the photo below, the PCB for the back output connectors are also visible.



The heatsinks have short, stubby teeth.

On the other side, you can see that the fan leads are not soldered on, which is useful if you want to swap out the fan. Whether you need or want to is something we'll find out.



The smaller capacitors here are rated at 105°C, and they appear to be one of the high quality Japanese brands.

FAN

The 120x25mm fan is branded as an Enermax, with two ball bearings. A model number search on the web turned up nothing useful, so all we can say is that dual ball bearing fans are often not quiet, and clear plastic blades often seem to make more resonant noise. However, some of the quietest PSUs we've tested also run fans that are not particularly quiet in normal usage; its their fan / thermal control system which makes them quiet. As always the proof will be in the listening. The 0.3A rating suggests that this fan might have a rated speed of 1500~2000 RPM, based on previous observations of 120mm fans. The following graph from Enermax's Modu82+ PDF prochure suggests a top speed of 1500 RPM.

It also happens to be a 4-wire PWM fan, which has an impact on the way we test, as you'll see in the next page.



A clear-bladed fan of unknown origins, branded as an Enermax.

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

target="_blank">Form Factors

. The ATX12V Power Supply Design Guide is the most referenced PSU standard in the computer industry. This guide is part of Intel's Power Supply Design Guide for Desktop Platform Form Factors, now in Revision 1.2, dated Feb 2008.

For a complete rundown of testing equipment and procedures,
please refer to target="_blank">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.

A TWIST IN FAN SPEED MONITORING

In our usual test methodology, the voltage to the fan is monitored with a multimeter by tapping the fan wires. This was not possible to do with the fan in the Modu82+ 625 because it is controlled with PWM, and thus the voltage would always read as 12V.



4-pin connector indicates PWM fan control.

Another method of fan speed monitoring had to be used. We opted for our optical (laser) tachometer. It requires a reflective piece of tape to be affixed to one of the blades, then counts the rotations to determine RPM.



Reflective tape affixed to one of the blades for RPM monitoring.

This meant we could not monitor the fan speed continuously, as the fan is located on the bottom of the PSU, which faces the inside of our thermal simulation box. The exhaust fan had to be removed from the PSU thermal simulation box
in order to gain access to the bottom of the PSU where the fan could be seen. We did a fan speed check just before and right after each power load change.



The only way for the optical tachometer to "see" the blades of the PSU fan.

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 also influence the PSU fan speed. Our PSU
test rig is a thermal challenge for a power supply:
A portion of the heat generated inside the case must be exhausted
through the power supply, which causes a corresponding increase in fan
speed. This replicates conditions inside a typical PC.

When examining the 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 18~20 dBA. AC input was 118~121V,
60Hz.

cellspacing="1" height="264" width="650">
OUTPUT, VOLTAGE REGULATION & EFFICIENCY: Enermax Modu82+ 625











DC Output Voltage (V) + Current (A)

Total DC Output

AC Input

Calculated Efficiency
+12V1
+12V2
+5V
+3.3V
-12V
+5VSB
12.26
0.98
5.16
0.99
3.36
0.95
–
0.1
21
31.5
66.1%
12.26
0.98
12.26
1.72
5.16
0.99
3.36
0.95
0.1
0.1
43
55
78.4%
12.24
1.89
12.24
1.72
5.16
1.98
3.36
2.64
0.1
0.3
66
82.5
80.0%
12.23
1.86
12.24
3.41
5.13
2.89
3.29
2.56
0.1
0.3
91
112
80.9%
12.21
4.68
12.21
4.92
5.12
3.75
3.31
2.52
0.2
0.4
149
177
84.3%
12.16
5.56
12.16
6.54
5.12
5.56
3.30
5.26
0.4
0.8
202
235
85.9%
12.14
6.62
12.14
7.95
5.10
7.36
3.30
7.23
0.4
1.0
248
287
86.4%
12.09
8.60
12.09
9.63
5.06
8.27
3.29
8.48
0.4
1.2
301
352
85.4%
12.06
11.26
12.06
12.67
5.05
11.65
3.29
12.40
0.5
1.6
401
478
83.8%
11.95
12.79
11.95
14.50
5.03
15.58
3.28
14.40
0.6
2.0
497
608
81.7%
11.90
20.60
11.90
16.63
5.00
18.43
3.28
17.93
0.8
2.5
625
790
79.1%
Crossload Test*
11.90
24.42
11.90
24.30
5.11
0.98
3.34
0.95
0.1
0.1
590
717
82.3%
+12V Ripple (peak-to-peak): 22mV @ 90W, rising to a max of 63mV @ full load

+5V Ripple (peak-to-peak): [email protected] 90W, rising to a max of 34mV @ full load

+3.3V Ripple (peak-to-peak): [email protected] 90W, rising to a max of 24mV @ full load

Maximum +12V Ripple during the Crossload Test was 82mV.
*For the crossload test, the 12V line is maximized,
and the +5V and +3.3V lines are set to just 1A.



NOTE:
The current and voltage for -12V and +5VSB lines are not measured
but based on switch settings of the DBS-2100 PS Loader. It is a tiny portion
of the total, and potential errors arising from inaccuracies on these
lines is <1W.


cellspacing="1" height="239" width="600" ">
OTHER DATA SUMMARY: Enermax Modu82+ 625
Output (W)
21
43
66
91
149
202
252
301
401
497
625
Intake (°C)
22
23
25
27
32
33
33
33
40
41
44
Exhaust (°C)
26
27
32
34
39
42
43
43
48
50
56
Temp Rise (°C)
4
5
7
7
7
9
10
10
8
9
12
Fan RPM
490
490
506
510
512
600
720
860
1180
1730
1780
SPL ([email protected])
19
19
19
19
19
20
21
22
26
36
37
Power Factor
0.92
0.94
0.98
0.98
0.98
0.98
0.99
0.99
0.99
0.99
0.99

AC Power in Standby: 2.3W / 0.38 PF

AC Power with No Load, PSU power On: 8.9W / 0.8.4 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 — This is a measure of AC-to-DC conversion efficiency. The ATX12V Power Supply Design Guide recommends 80% efficiency or better at all output power loads. 80% efficiency means that to deliver 80W DC output, a PSU draws 100W AC input, and 20W is lost as heat within the PSU. Higher efficiency is preferred for reduced energy consumption and cooler operation. The latter allows reduced cooling airflow, which translates to lower noise.

With its claim of 88% efficiency at 230VAC input, we knew the Modu82+ would be efficient. Our test sample reached >86% efficiency even with 120VAC input at ~250W output, and as you'll see below, reached 89% efficiency with 240VAC input. This is very impressive performance, not quite matched even by the most efficient PSUs we've tested. At the lower end with 120VAC input, it hit 66% at 21W, 78% at 43W, and 80% at 66W,
which are excellent results. Bear in mind that many modern systems spend most of
their time idling within this modest range.

Note that the the measured efficiency dropped below 82% at 500W load, and below 80% at 625W load. Does this contradict the report from 80 Plus which shows >82% efficiency at full power? No, not really. The 80 Plus testing procedure does not take thermal conditions into consideration; the PSUs are tested in typical room temperature, most often 20~25°C. Our testing does not coddle the PSUs in this way; the ambient working temperature of the PSU rises with the power load, as would be the case in a real system. The Enermax is rated for full power operation up to 40°C. The intake temperatures in the test environment at 500W and 625W loads were 41°C and 44°C, respectively; it's no surprise that the efficiency dropped a bit.

2. VOLTAGE REGULATION refers to how stable the output voltages are under various load conditions. The ATX12V Power Supply Design Guide calls for the +12, +5V and +3.3V lines to be maintain within ±5%. The Modu82+ 625 had excellent VR,
staying within +2% and -1% on the important 12V line though all the tests, even the extreme crossload test. It was similar on the +5V and +3.3V lines.

3. AC RIPPLE refers to unwanted "noise" artifacts in the DC output of a switching power supply. It's usually very high in frequency (in the order of kilohertz or megahertz). The peak-to-peak value is measured. The ATX12V Guide allows up to 120mV (peak-to-peak) of AC ripple on the +12V line and 50mV on the +5V and +3.3V lines. Ripple on the Modu82+ was quite modest on all the voltage lines, well within the ATX12V specification.

4. POWER FACTOR is ideal when it measures 1.0. In the most practical sense, PF is a measure of how "difficult" it is for the electric utility to deliver the AC power into your power supply. High PF reduces the AC current draw, which reduces stress on the electric wiring in your home (and elsewhere up the line). It also means you can do with smaller, cheaper UPS backup; they are priced according to their VA (volt-ampere) rating. PF on this sample was close to perfect across all loads, as is the norm
for most power supplies with active PF correction circuitry. It wasn't quite
perfect at the very low end, with a ratio of 0.92 at 20W, but this is a lower
load than the MODU+ 625 will ever realistically face.

5. AC INPUT VOLTAGE TESTS

LOW VAC INPUT: This is to check the stability of the PSU under brownout conditions where the AC line voltage drops from the 110~120V norm. The Modu82+ is rated for 100VAC minimum input; it was pushed down to 90VAC without any problems. DC output voltage regulation remained unchanged from that achieved at 120VAC.

LOW VAC TEST: Enermax Modu82+ 625 @ 500W load
VAC
AC Power Input
Efficiency
120
612W
81.70%
110
619W
80.78%
100
625W
80.00%
90
632W
79.11%

EFFICIENCY WITH 240 VAC INPUT: Most power supplies achieve higher efficiency with higher AC input voltage. SPCR's lab is equipped with a 240VAC line, used to check power supply efficiency for the benefit of those who live in 240VAC mains regions. The 240VAC efficiency advantage measured nearly 4 percentage points higher at 500W load, but it dropped to under 3 percentage points at 250W output. At lower loads, it will drop further, probably to about 2 percentage points.

DC Output
240VAC Input
120VAC Input
Power
Efficiency
Power
Efficiency
250W
280W
89.3%
289W
86.5%
300W
340W
88.2%
350W
85.7%
500W
585W
85.5%
612W
81.7%

6. LOW LOAD TESTING revealed no problems starting at low loads. The power draw at standby was a modest 2.3W, and power
consumption with no load was good at 8.9W.

7. FAN, FAN CONTROLLER and NOISE

There's no doubt about it: We have a new quiet champ. This Modu82+ sample's acoustics upon turn-on were so low that I had to take a close look to make sure the fan was actually spinning. Never mind the earlier comments about double ball bearings or clear plastic blades; this fan is clearly the quietest we've ever heard in a stock power supply — well, close to NOT heard. The measured SPL of 19 [email protected] was just a single decibel higher than the 18 dBA ambient of the room. During the day, I could not clearly hear the PSU fan from a meter away, but the SLM could.

This SPL measurement was actually made at about one o'clock in the morning. The ~20 dBA typical ambient in the lab during the day was too high to get clear readings. Also, every other electrical device in the room had to be unplugged or turned off: Every wallwart, power brick, and even the CFL lights — in order to eliminate all other low level buzzing or humming sounds to isolate the PSU's contribution to the SPL from a meter away.

From about six inches away, the acoustic signature was primarily a mild electrical buzz, audible over a very soft touch of broadband noise from the fan. It was hard to believe that the fan was even spinning, but the telltale flow of air could be felt on my hand. I can only conjecture how exactly Enermax managed to obtain such a smooth, soft noise from their seemingly ordinary fan. Perhaps their implementation of PWM control is perfectly matched to this fan. At the ~500RPM start level (they say 450RPM), it's at least as quiet as any fan I've listened to. That says a lot; I've played with and listened closely to literally hundreds of fans over the years.

Amazingly, the fan stayed at the same barely audible level all the way to around 200W ouput when it made its first small step up to 600RPM and 20 [email protected] Even at 300W output, the fan was still spinning only at 720RPM, with a measured SPL of just 22 [email protected] At 400W load, the fan had spun up only to around 1200RPM, and the SPL measured just 26 [email protected] It was a smooth broadband sound. Beyond that level, the fan ramped up quickly, as expected, peaking out at 37 dBA beyond 500W.

Comparison: PSU Noise (in [email protected]) Vs. Power Output
Model
65W
90W
150W
200W
250W
300W
400W
500W

Enermax Modu82+ 625W
19
19
19
20
21
22
26
36
Corsair HX520/620
22
22
22
22
22
22
29
43
Seasonic S12 Energy+ 650
20
20
20
20
21
25
38
38
Corsair VX450
21
21
21
21
22
26
44
-
Seasonic M12II-430
21
21
21
24
28
35
41
-
Seasonic S12II-380
21
21
21
21
25
31
39
-

Zalman ZM460-APS
22
23
26
29
31
34
37
37

Enermax Liberty 500/620
21
21
24
30
35
38
41
41

The table above shows measured noise-to-power data from selected reviewed PSUs. The green cells are all the values that are 30 dBA or higher; <30 [email protected] or lower is SPCR's SPL definition of "quiet". The data shows clearly that the Modu82+ starts at a lower noise level and stays quieter than any other PSU all the way to 500W (and beyond). The differences at the lower power levels are small, but they will be audible if your ambient threshold noise is low enough. At the higher power levels, the Modu82+ acoustic advantage increases significantly against most other PSUs.

CAUTION: Please keep in mind that the above results cannot be considered absolutely "correct". It tells about PSU samples in our test rig. The thermal fan control employed in every one of these power supplies interacts with the working environment, which means in that different environments (read systems: case, components, configuration, etc.), the results are bound to vary.

8. TEMPERATURE & COOLING

The Modu82+ 625W displayed an unusually low temperature rise throughout the load testing. The temperature rise was held to under 10°C until 250W load. As the fan sped up in response to increasing heat, the temperature rise dropped again into single digit numbers over 300W, till beyond 500W. However, it's also important to know that the actual temperature (not the temperature difference) inside the PSU load tester was higher at a given power load level than with many other PSUs. This is a direct result of the slower spinning fan used in the Modu82+, which suggests that the PSU should not be relied to provide any cooling for the system other than itself. Similar comments can be made for some of the other quiet PSUs at the top of our recommended PSU list, such as the Seasonic S12 550 / 650 Plus and the Corsair HX series.

The temperatures reached during full load power test (44°C in, 56°C out), along with the drop in efficiency to below 80% tells us that at such high power loads, your system would do well to have better cooling than our PSU load tester. However, sustaining such a high power load is no easy task outside a lab test setting, with a real computer. For an analysis of real PC power needs, please check the section Real System Power Requirements in our reference Power Supply Fundamentals article.

AN ASIDE: Three 12V lines? The Modu82+ is said to have three 12V lines each capable of delivering a maximum of 25A and a combined (simultaneous) total of 50A. This means it has three current limiters on three bundles of 12V wires, with each limiter set to 25A. However, it's not clear which wires being together in each bundle. We did not trigger any 12V/25A limiters during our testing.

MP3 SOUND RECORDINGS

These
recordings were made with a high resolution, studio quality, digital
recording system, then converted to LAME 128kbps encoded MP3s. We've
listened long and hard to ensure there is no audible degradation from
the original WAV files to these MP3s. They represent a quick snapshot
of what we heard during the review. Two recordings of each noise level
were made, one from a distance of one meter,
and another from one foot away. More details about how we make these recordings can be found in our short
article: Audio
Recording Methods Revised
.

The
one meter recordings
are intended to give you an idea of how the subject
of this review sound in actual use — one meter is a reasonable typical
distance between a computer or computer component and your ear. The
recording contains stretches of ambient noise that you can use to judge
the relative loudness of the subject. Be aware that
very quiet subjects may not be audible — if we couldn't hear it from
one meter, chances are we couldn't record it either!

The
one foot recordings
are designed to bring out the fine details of the
noise. Use this recording with caution! Although more detailed, it may
not represent how the subject sounds in actual use. It is best to
listen to this recording after you have listened to the one meter
recording.

Each recording starts with 6~10 seconds of room ambience, followed by 10 seconds of
the product's noise. For the most realistic results, set the volume
so that the starting ambient level is just barely audible.

NOTE: The low acoustic level of the Modu82+ meant that the same extra care and effort that went into measuring the SPL also went into making audio recordings. They were done at the same time, between 1~2AM on a quiet, still night. (Wind noise is insidious when you're trying to record very quiet sounds.) Be forewarned: Unless you have a good pair of headphones or speakers connected to a decent amplifier with low noise, you may have a hard time hearing the lowest level recordings.

On the 19 [email protected] recordings, please don't turn the volume way up without listening through them all the way at least once at a modest level. There's an audible CLICK about 8 seconds into each recording; this is the sound of the PSU being switched on, left in place to make sure you know when the PSU was turned on.

  • Enermax Modu82+ 625W at 20~150W output, 19 [email protected]: href="/files/sounds/psu/enermax-modu82-19dba-1m.mp3">One meter recording, One foot recording
  • Enermax Modu82+ 625W at 300W output, 22 [email protected]: href="/files/sounds/psu/enermax-modu82-22dba-1m.mp3">One meter
  • Enermax Modu82+ 625W at 400W output, 26 [email protected]: href="/files/sounds/psu/enermax-modu82-26dba-1m.mp3" target="_blank">One meter

Sound Recordings of PSU Comparatives

CONCLUSIONS

The top ranks of the quietest fan-cooled power supplies have seen little movement in the last couple of years. Seasonic dominates, along with Corsair and Antec, whose quietest PSUs are made, amusingly, by Seasonic. Other brands have made it onto our Recommended PSU list, including Nexus, Enermax, Silverstone, and Zalman, but at the very top, it's been a one-company show for some time. The Modu82+ 625 is the first power supply made by a company other than Seasonic to take the highest position as the quietest fan cooled PSU reviewed by SPCR. Considering that we are the choice review site for brands catering to the quiet PC market, it's likely that the Modu82+ is, in fact, the quietest fan-cooled PSU in the world today.

The near-inaudible acoustics of this Enermax do not come at the expense of other performance aspects. On the contrary, the efficiency is as high as any PSU we've tested, probably higher; voltage regulation is very tight; the ripple noise is low; and cooling is certainly good enough (in any real use, rather than prolonged, constant full power output lab test — utterly unlikely in real use). By any standard, the Modu82+ 625 is an excellent power supply.

Having crowned a new silent PSU king, it's prudent to point out that in a competition among the best in any category, whether Olympic athletes or high performance computer power supplies, the differences between first, second and third place (and even lower ranks) are often marginal. With swimmers, runners, and skiers, it's sometimes measured in hundredths of a second. Similarly with quiet, high performance PSUs, a number of Seasonic and Corsair models come within 1~2 [email protected] of the Modu82+ 625's default acoustics, and their electrical performance is close enough to be considered identical. In practical usage, the noise advantage between this PSU and some of the other top ranked quiet models may not even be audible because of the masking effects of other louder noise sources, either in the computer or in the environment. The noise advantage will also be insignificant if you're going to run this (or any other) PSU above the "hinge" point of the noise/load curve; once this point is exceeded, the differences between the various top models becomes truly moot — basically they all get too loud to be called "silent". So those who already use one of SPCR's top-rated PSU can rest assured that there no need to rush out for a Modu82+ replacement.

But if you are starting out from scratch, you have a truly low ambient noise environment, and you seek to build an inaudble PC without the complexities of a fanless PSU, then a Modu82+ is a worthwhile purchase. It will make less contribution to the overall noise of the PC than any other PSU, by a small margin.

All this assumes that we were not sent some carefully-tweaked, golden sample meant to wow the crazy, quiet-obsessed, reviewers at SPCR. Our Enermax contact assures us that this sample is exactly the same as the packages going to the stores. It was the first of a small handful of Modu82+ samples that arrived at their US office in January without the retail box — because the new box had not been ready yet. I have no reason to doubt these words, and at least one other sample has been promised within the next two weeks, along with samples of the lower power models.

The Enermax Modu82+ 625 is a great addition to the world of quiet PC components. It cuts the quiet edge just a little bit closer to the nirvana of silence while making worthwhile incremental gains in energy efficiency. The other PSU brands have reason to sit up and take notice, as do any DIY computer enthusiast who prefer their computers to be strong, silent types. Highly recommended.

Much thanks to Enermax
USA
for this review sample.

* * *

WARNING! There are many reports from users of
the fan in this PSU going bad (noisy, clicky) after just a few months use.
Since the remarkable performance of the fan in our sample is a major reason
for our strong recommendation, potential buyers are cautioned.

SPCR Articles of Related Interest:

Power Supply Fundamentals

Recommended Power Supplies

Power Distribution within Six PCs

SPCR PSU Test Rig V.4.1

Seasonic S12 Energy Plus 550/660

Corsair HX520W & HX620W Modular Power Supplies

* * *

href="http://www.silentpcreview.com/forums/viewtopic.php?t=46778"
target="_blank">Discuss this article in the SPCR Forums.

POSTSCRIPT, April 3, 2008: Not a PWM Fan

Here's something of interest that came from Enermax recently. It's regarding the fan, which shocked me with its smooth quiet performance in our review sample:

The new Enermax MODU82+ and PRO82+ series power supplies use a new patented SpeedGuard control circuit to achieve low fan RPM and extremely low noise without any negative effects. The patented control circuit requires a unique fan with a 4-Pin power connector, like a PWM fan. But this is not a PWM fan; it is a patented bi-voltage fan.

To clarify:

1. Enermax's new SpeedGuard control circuit does not require an expensive PWM fan; instead, they use a new special design fan which offers low RPM with higher CFM.

2. The new MODU82+ and PRO82+ series PSU fan cannot be substituted with a standard 3-pin fan or a 4-pin PWM fan. Doing so may cause the substitute fan to not run, run only at full speed, or be damaged. There is also a risk of damage to the SpeedGuard control circuit. The 4-pin configuration is not standard.

Conclusion: Do not modify ENERMAX MODU82+ or PRO82+ PSU models with any other fan (unless you have a very good understanding of electronics and you're willing to void the warranty). The fan control circuit in these new PSUs can only work with their own stock fan.

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