Enermax Eco80+ 500W PSU

In Enermax’ seven (!) lines of power supplies, the Eco80+ is one of two tagged as “eco”. The “Love our Earth” tagline on the packaging attests that “eco” stands for ecology, but its position at the low-end of Enermax’ lineup suggests that “economy” might also be a relevant tag. How fares this modest PSU in these times of silent, 90% efficiency, $200 models?

In Enermax’ seven (!) lines of power supplies, the Eco80+ is one of two tagged
as “eco”. The “Love our Earth” tagline on the packaging
attests that “eco” stands for ecology, but its position at the low-end
of Enermax’ lineup suggests that “economy” might also be a relevant
tag. Certainly, there is little to suggest the Eco80+ is more environmentally
friendly than any other power supply. Its most likely selling point —
efficiency — is overshadowed by the fact that nearly every other model
Enermax produces matches or exceeds the efficiency of the Eco80+ (as certified
by 80 Plus). The best that
can be said is that ecology and economy are often tied: Buying a cheaper product
sometimes means less packaging and less energy expended to create it.

Putting aside the green marketing for now, Enermax is a respected brand, and
a “basic” 500W model appeals well to our sense of simplicity. It also
has an unusual fan — always a point of interest to us. Enermax has dressed
it up in fancy marketing terms, but it appears to be a descendant of Enermax’
Enlobal bearing Marathon fan. Jonny Guru spent an entire review mocking
the “Magma” fan, its “Twister” bearing, and its “Batwing”
blades, but the technology piqued our interest before, and we are happy to take
another look at it.

PACKAGING & FEATURES

Technically, yes, the is a green box … but only if you’re talking in terms of the color of the light it reflects. Enermax’ “green” marketing hasn’t convinced me this is good for the environment.

Nonessential accessories are limited to a pair of cable ties.

A 500W power supply is plenty; none of the lines are likely to come anywhere near their rated maximum during ordinary use. You’d need at least a pair of top end graphics cards to push the power load anywhere close to maximum. Ordinary computer users can easily get by with half as much capacity, but 500W is still considered a “small” power supply these days…

VISUAL TOUR

The finish for the Eco80+ is matte black, which is pretty common these days. It’s accented by a gold grill and the bright orange-red fan blades. In other words, it has enough paint to look passable but it’s nothing too special. But then, appearance isn’t really the best way to judge a power supply anyway.

MAGMA FAN (Twister bearing, Batwing blade, Buzzword loaded)

Despite the buzzwords, the fan is actually worth a closer look.
The “twister” bearing appears to be a variant of the magnetic bearing
used in Enermax’
Marathon fans. The technology piqued our interest when we looked at it before
because it was generally extremely quiet and exhibited very little increase
in noise as the fan speed increased. The double-ridged “Batwing” blades
are new to us, and it’s hard to say how effective or ineffective they are. The
thermal results should tell us whether the fan is adequate when we get to that
part of the review later.

The fan is also available individually
from Enermax, and anecdotal feedback from SPCR forum members has generally
been positive. As with the Marathon fan that we looked at, the fan blade assembly
can be removed and cleaned, though we would caution most users from opening
their power supply unless they feel comfortable working with high power electronics.
Enermax also touts a long lifetime (100,000 hour MTBF @ 85°C) as one of
the benefits, but it’s nearly impossible to verify such a claim. Power supplies
are high heat environments though, so it’s good to know the fan is specified
for a high temperature.

The metal frame is tapered to minimize the gap between the fan and the frame.

Enermax’ attention to noise extends beyond just the fan itself. The edges of
the frame around the intake are tapered downwards to minimize the gap between
the frame and the fan. The idea is to reduce turbulence, but given how many
other closely spaced components there are in the air path, it seems unlikely
to have a major effect. Still it’s nice to see this level of attention to noise.

Strangely enough, Enermax has managed to obtain a patent for this simple concept
(eliminating gaps to reduce turbulence noise), though the relationship between
gaps and turbulence is hardly a secret.

When the fan was running, there was a significant amount of backdraft leaking
out from around the edges of fan blades. With the fan going full tilt, it was
easier to feel the air being forced backwards around the edges of the fan than
it was to feel the main current through the intake.

A clear plastic baffle masks off the front half of the airflow to prevent “short-circuit” airflow in which the air would flow directly from intake take exhaust without passing over the hot internal components.

The fan is a four pin PWM controlled model, making it impossible for us to measure
fan voltage.

We have high hopes for the fan, but those who like fan swapping should note
that the Magma fan is a 4-pin PWM controlled model that cannot be replaced by
just any fan. This type of fan allows very precise speed control, but, as always,
it will be the quality of the fan controller that determines how noisy or quiet
the power supply is in actual use.

OUTPUT CABLES

Many of the cable sets are “forked”.

Cables on the Eco80+ were a little unusual in that several of the cable sets
are split so that multiple cable sets end up sharing a single fat cable as they
come out of the power supply. The splitting is facilitated by vinyl sleeving,
which holds the cable sets together in a single manageable bundle. It’s an interesting
approach to cable management, and we are curious to see how effective it is
in actual use.

All cables are sleeved up to the first connector except where otherwise noted.

• Main ATX connector, 24-pin (21″)
• CPU AUX connectors, 4+4-pin, each section on its own tail
  • 4-pin AUX (22″)
  • 2nd half of 8-pin AUX (22″) (mates with the first 4-pin connector
    to create an 8-pin EPS connector)
• PCI-e connectors (cable splits in two at 11″)
  • 6-pin PCI-e (17″)
  • 6+2-pin PCI-e (17″)
• Accessories (cable splits in three at 6″)
  • 3x IDE power connectors and 1x Floppy connector (29″)
  • 4x SATA power connectors (29″)
  • 2x SATA power connectors and 2x IDE power connectors (33″)

The mixed SATA / IDE cable will probably be appreciated, since it will allow
most basic configurations (with SATA hard drives and a single optical drive)
to be wired with a single cable set. However, the order of the connectors seems
wrong; with the power supply located in the standard ATX position above the
CPU, the optical drives are closer to the power supply, and should thus the
IDE connectors should be first in the chain. On the other hand, the order is
correct when mounted in a case such as the
Antec P183 that locates the power supply at the bottom.

INSIDE

Things look pretty normal under the hood with all of the usual components in
the usual places. The input capacitor is rated for 85°C, but the outputs
are all 105°C.

One thing that did strike us was how neatly all of the output wires were routed
as they left the casing. The exposed solder points for all the output wires
were also coated in heatshrink.

TESTING

For a fuller understanding of ATX power supplies, please read
the reference article Power
Supply Fundamentals. 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 V4.1. The testing system is a close simulation of
a moderate airflow mid-tower PC optimized for low noise.

Acoustic measurements are now performed in our anechoic chamber with ambient level of 11 dBA or lower, with a PC-based spectrum analyzer comprised of SpectraPLUS software with ACO Pacific microphone and M-Audio digital audio interfaces.

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.

REAL SYSTEM POWER NEEDS: While we test the PSU to full
output in order to verify the manufacturer’s claims, real desktop PCs simply
do not require anywhere near this level of power. The most pertinent range of
DC output power is between about 40W and 300W, because it is the power range
where most systems will be working most of the time. To illustrate this point,
we
conducted system tests to measure the power draw of several actual systems
under idle and worst-case conditions. Our most power-hungry overclocked
130W TDP processor rig with an ATI Radeon X1950XTX-512 graphics card drew ~256W
DC peak from the power supply under full load — well within the capabilities
of any modern power supply. Please follow the link provided above to see the
details. It is true that very elaborate systems with the most power hungry dual
video cards today might draw as much as another 150~200W, but the total should
remain under 500W in extrapolations of our real world measurements.

INTERPRETING TEMPERATURE DATA

It important to keep in mind that PSU fan speed varies with temperature,
not output load. A power supply generates more heat as output increases, but
this is not 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:

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

The ambient temperature was 23°, and the ambient noise level
was 11 dBA. AC input voltage was 118~121V.

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.
It allows reduced cooling airflow, which translates to lower noise. The 80 Plus
standard requires a minimum of 80% efficiency at 20%, 50%, and 100% of the rated
maximum load.

There was a time when 80% efficiency at 90W output and above would
have been top notch performance. No more — with the latest power 80 Plus
Gold power supplies breaching 90% regularly, an 84% peak efficiency is a bit
of a yawn. It merits basic 80 Plus certification, but does not meet any of the
higher standards.

That said, it’s helpful to put things in perspective. At 200W
output (above the maximum power usage for most normal systems), the AC power
consumption difference between the Eco80+ and the record-breaking Seasonic
X-650 is 20W. That’s not nothing, but it’s not a whole lot either. That
20 watts is likely more important in what it means for cooling (and thus noise
and reliability) than what it means to the environment.

2. DC 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 maintained within ±5%.

Unless a unit goes into overload, it’s rare that we see significant
problems with voltage regulation. The Eco80+ is no exception — it was nearly
always within ±2% and it never exceeded ±3% on any line. With
the exception of the cross-load test (which is strenuous), the +12V line stayed
above the specified +12V at all times.

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 100s of kHz). 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. Where voltage regulation is a measure
of variance from spec, ripple is more a measure of tolerance: How much the voltage
is changing at any given time. Ripple is of interest to over- and under-clockers
who push their systems to the limits of what they are actually capable
of rather than relying on what the specs say they should be capable of.

Ripple on the Eco80+ was generally around 20 mV on all lines,
and it changed very little as load increased. These are good numbers —
well within spec — the lack of change as the load was increased is a good
sign.

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 a smaller, cheaper
UPS backup; they are priced according to their VA (volt-ampere) rating.

As is the case for most units with active power factor correction
(which, these days, is most reputable brands), PFC was close to perfect, starting
at 0.91 for the minuscule 20W load, and staying at 0.98 and above through most
of the common operating range.

5. LOW LOAD TESTING revealed no problems starting at very
low loads and it stayed operational with no load applied. The low 6.1W baseline
power consumption is reflected in the relatively high efficiency at low loads
where the baseline “overhead” makes up a proportionally larger amount
of the power lost to heat.

6. TEMPERATURE & COOLING

The thermal design of the Eco80+ is probably its weakest point.
While we saw no signs that temperature was a problem for stability, the thermal
rise was higher that we would like. This is probably tied to the speed of the
fan, since the temperature rise was very sensitive to changes in fan speed,
suggesting that the fan controller did a good job of keeping the fan speed right
on the edge of the threshold needed to evacuate heat adequately.

This is an engineering tradeoff. Low fan speed means low noise
— something we wholeheartedly approve of. And, so long as the internal
components are of high quality and heat tolerance, a higher thermal rise at
low loads is not a bad thing. Judging by the rest of the performance numbers,
component quality should not be an issue. Just don’t count on the Eco80+ to
remove a lot of heat from your system; this is standard advice for anyone using
a quiet PSU.

At higher loads (>400W) it’s a different story. Once the thermal
rise hits ~15°C or more, there is cause for concern, especially if the power
supply is likely to see long term stress at these levels. The situations where
this actually happens are few and far between, but we don’t recommend using
this power supply with multiple graphics cards.

7. FAN, FAN CONTROLLER and NOISE

The fan controller holds the fan speed down until absolutely necessary.
The fan didn’t speed up significantly until the 200W output load was reached
— above the maximum output for most normal usage patterns.

For once though, our highest praise isn’t for the controller but
the fan itself. If we had reservations about resonance and directional noise
the last time we saw an Enermax fan, these concerns are no more; the noise profile
of the Magma fan is outstanding. The highest SPL we measured was 33 dBA@1m,
and this was only after 15 minutes at maximum output capacity. As a maximum
noise level, that’s an excellent result — only 3 dBA off our (somewhat
arbitrary) 30 dBA line between noisy and quiet.

More importantly, at realistic loads, it remained well
under that 30 dBA line, and often under 20 dBA. Other than certain dead-of-night
exceptions, most environments are above 20 dBA, and thus noise below this level
can be considered close to inaudible. The Eco80+ was below 20 dBA for all loads
below 250W. Let me restate that in practical terms: In the vast majority of
surroundings, for the vast majority of systems, the Eco80+ is likely to be inaudible.

Most impressive of all was the baseline noise level at 90W and
below where I was unable to hear it in our anechoic chamber from our usual
operating position of one meter. I had to hold my ear up to the unit —
I would guess within eight inches — to hear the faint hum that indicated
that the fan was spinning at all. Our SPL meter agreed — it did not rise
above the 11 dBA ambient level, though a small increase was visible in the frequency
graph.

Describing the quality of the noise seems a little moot, since
it took great effort to get the fan spinning fast enough for noise quality to
matter. So, as a footnote: The noise quality was smooth and generally low pitched.
Unusually for a fan, the pitch did not increase much with speed, making the
speed changes less noticeable.

11 dBA@1m / <90W. Yes, the fan is spinning here. The noise profile at 90W and below just barely registers in our anechoic chamber — quite an accomplishment. Most of the energy is concentrated below 400 Hz where we are less sensitive to noise. 19 dBA@1m / 250W. The frequency response of the fan is clearly visible by this time, mostly concentrated between 150 and 400 Hz. Above 2,000 Hz, there is almost nothing. 26 dBA@1m / 300W. The fan is now plainly audible. The frequency spectrum hasn’t really changed too much, but there’s a lot more energy in the 600 to 2,000 Hz range. This is where the ear is most sensitive, and accounts for the large jump in SPL reading. The fan is still mostly invisible above 2,000 Hz, and the few peaks that are visible here are hard to hear because of the masking effect of the lower frequencies.

One thing we’ve been examining with especially quiet power supplies
is how the power supply performs outside the tough thermal conditions of our
standard test. The recent popularity of cases that isolate the power supply
from the rest of the system make this a relevant question, as the cooler intake
air allows the fan to run slower and quieter. We examine this by rerunning some
of the high load tests with the power supply in free air, away from the tough
thermal conditions of the hot-box.

The results were quite dramatic: Even at full load, the SPL remained
below 30 dBA, and at 400W, SPL dropped from 32 dBA@1m to 23, which soubd subjectively
like half the noise. If you can keep the rest of your system stable and below
23 dBA at a sustained load of 400W, this reviewer will be very impressed (in
fact, he’ll probably invite you to write an account of how you did it for SPCR).

COMPARISONS

The comparison table below shows the SPL versus Power Load data on all the
PSUs tested in the anechoic chamber thus far. It’s difficult to rank them, as
the measured SPL varies with power load. The Eco80+ is louder in our hot box
at 300W than many of the others, but at below 200W, it’s one of the quietest.
Overall, the Eco80+ compares favorably with the best of the best for a <250W
system; if it is used in a thermally advanced chassis with seperate air intake
for the PSU, then that power ceiling would move up another 100W.

Although the fan curve of the Eco80+ seems to rise more quickly than some of
the the other PSUs at the top of the list, its extremely low baseline noise
and excellent noise character make it a superior choice for regular use scenarios
(<250W). In practical terms, there is very little difference between the
top six or so power supplies on this list. They’re all pretty near silent.

Caution: Please keep in mind that the data in the above table is specific to the conditions of our test setup. Change the cooling configuration, the ambient temperature and any number of other factors, and you could change the point at which the fans start speeding up, as well as the rate of the rise in speed. The baseline SPL is accurate, however, probably to within 1 dBA.

MP3 SOUND RECORDINGS

These recordings were made as 24-bit / 88 kHz WAV files with a high
resolution, lab quality, digital recording system inside SPCR’s
own anechoic chamber (11 dBA ambient), 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.

These recordings are intended to give you an idea of how the product sounds
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!

Each recording starts with 6~10 seconds of room ambient, 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, then
don’t change the volume setting again while comparing all the sound files.

• Enermax
  Eco80+ at various loads in anechoic chamber at one meter
  — idle to >90W (11 dBA@1m)
  — 200W (16 dBA@1m)
  — 250W (19 dBA@1m)
  — 300W (26 dBA@1m)

Sound Recordings of PSU Comparatives
in the Anechoic Chamber

CONCLUSIONS

While bleeding edge power supplies are pushing 90% efficiency (and
$200), it’s good to see that the lower end of the market is thriving as well.
The Eco80+ is Enermax’ economy line, but it’s still a very worthy power supply.
Sure, it’s not really tops in any particular category, but it still exceeds
the requirements of most systems out there. Unless your workstation needs (and
I mean really needs) multiple blazing graphics cards, the difference between
an Eco80+ and a Seasonic X-650 is mostly bragging rights.

It’s wonderful to discover that even this lowly power supply has
a noise profile that matches the best. Bad as they are, Enermax’ overwrought
marketing buzzwords can be forgiven because the Magma fan — with its Batwing
blades and its Twister bearings — really is quiet. Exceptionally
so. We really need to get hold of some individual fan samples, because this
power supply is worth it just for the fan.

And what of the middling efficiency and cooling performance? It’s
good enough, and, especially if you go for the cheaper 400W version (the 350W
doesn’t seem to be carried anywhere), it’s much better value than the high end
competition.

Much thanks to Enermax
for this review sample.

The Enermax Eco80+ 500W is Recommended by SPCR

* * *

SPCR Articles of Related Interest:
Power
Supply Fundamentals
Recommended
Power Supplies
SPCR
PSU Test Rig V.4
Seasonic X-650: Seasonic Hits
Gold
Seasonic M12D-850W
Enermax
Modu82+ 625W
Antec CP-850: Unique PSU with Top Performance

* * *

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