ePower’s entry into the very quiet PSU realm is… “semi-fanless”, says our reviewer. No, this does not mean it has half a fan; rather its fan acts as if it’s not there half the time. The EP-450P5-L1 is much like the Phantom 500 in its basic operational premise, but the execution is quite different. It was very quiet much of the time on our test bench, but you will have to read the whole review to fully appreciate the Lion’s strengths and weaknesses.
October 27, 2005 by Devon
Cooke
| Product | ePower Lion EP-450P5-L1 450W ATX12V 1.3 Semi-Fanless Power Supply |
| Manufacturer | ePower Technology |
| Market Price | US$130 |
What do you get when you
take an ATX12V 1.3 power supply, equip it with connectors for the latest motherboards
and VGA cards, then keep the fan from turning on until it’s ready to overheat?
The ePower Lion EP-450P5-L1: A semi-fanless
power supply that bristles with bling and gadgetry.
ePower sells the Lion as a “better than fanless power supply”, with
a fan “which will kick into gear only when the system is executing a load
over 250W”. This is a lofty claim. The one other “hybrid” power supply we
looked at, the Antec
Phantom 500, powered up the fan once output hit 150W. Of course,
ePower does not specify how the 250W load was measured, and the 150W number
for the Antec comes from our own thermally realistic test setup, so it will be interesting
to see how the Lion fares in the same test. Fan
speed control in every PSU we’ve seen is based on temperature, not output load, so we will be sure to look at
the temperature when the fan turns on.
The Lion has many unusual features. Some of these
are just for bragging rights, but a couple are genuinely useful. ePower recognizes that cable management is an important part of system cooling, and
they include a package of multicolored velcro cable ties to help keep
cables where they belong. They also borrowed a feature from Antec’s power
supplies and included a number of “Fan Only” headers.
The retail package lists the Lion’s unofficial name: “Silent Engine”.
Included in the box: Power supply, power cable, velcro cable ties, and
an 8.5″ by 11″ leaflet that passes for an instruction manual.
In general, the Lion is poorly documented. Most of what we know of the
power supply was gleaned from experimentation with the product; neither
the manual nor the web site was very helpful. In several cases, features were
mentioned without properly explaining how to use them or what they do.
The main issue is language: The manual has some good examples of Engrish.
Quality of documentation is mainly a problem for users who have
never installed a power supply before. Inexperienced users would be well-advised
to find a properly written guide (about installing a PSU) on the web rather
than relying on ePower to help them out.
FEATURE HIGHLIGHTS
| Feature Highlights of the ePower Lion (from ePower’s | |
| FEATURE & BRIEF | COMMENT |
| Temperature Sensor: An amphibian temperature sensor lead out to the chassis. This feature add to the case cooing feature of E Power Technology’s power supply. The temperature sensor, together with the chassis fan lead, will regulated the case fan speed when the internal temperature rise than normal operation temperature. | The temperature sensor may be amphibian, but the rest of the power supply isn’t. We politely suggest not operating the power supply underwater. Joking aside, the temperature sensor refers to a thermistor |
| LED Fan: The Lion power’s better than fan-less design also add a blue color LED light to the stand-by fan, which will lights as the fan turns, another cool feature to the gaming PC system | Bling bling. |
| Case Fan Speed Control: To maximized the silent effect of E Power Technology’s silent technology. All E Power technology’s gaming power armed with 3 special power leads for case fans. These lead will reduced the noise level created by case fans. | See comment about Temperature Sensor. |
| SATA Power Lead: 2 SATA power lead on all E Power Technology’s gaming power supply. | Standard. |
| Enhanced VGA Power Lead: A patented special feature of the gaming power series. The VGA power lead comes with a RMI filter and wire coat to eliminate EMI‘s affect on VGA cards thus the ignoring snow and water wave effect will be reduced. A great plus for PC gaming. | Possibly useful when overclocking, bragging rights for everyone else. |
| Power Fan Control Switch: The Power Supply fan turns on automatically after reaching higher than 250W loading, or user have to option to turn on the fan at anytime. | The hard of hearing and the thermally paranoid can run the fan at full speed all the time; most people will want to let the fan be controlled automatically. |
OUTPUT SPECIFICATIONS
| SPECIFICATIONS: ePower Lion EP-450P5-L1 | ||||||
| AC Input | 100-120 / 200-240 VAC @ 60 / 50Hz | |||||
| Maximum AC Current | 10A @ 120V / 6A @ 240V | |||||
| DC Output | +3.3V | +5V | +12V | -12V | -5V | +5VSB |
| Maximum Output Current | 28A | 45A | 28A | 1.0A | 0.8A | 2.5A |
| Maximum Combined | 220W | 336W | 12W | 4W | 12.5W | |
| 450W | ||||||
The output specs show that the Lion is based on an old
design. A huge amount of current is available on the +5V rail, which
is hardly used by modern systems. The Lion also includes a -5V rail, which
has been obsolete since ATX12V 1.3 was released in April 2003. ePower states
that the Lion is compliant with ATX12V 1.3. The current version of ATX12V is
2.2.
In spite of its old design, the Lion has enough output capacity on its +12V
rail to power most modern systems. Only extremely high-end systems with multiple
CPUs and/or graphics cards could possibly demand more power than this PSU is rated to deliver. The cables and connectors have been updated
so that it can power the latest hardware: Both a 24-pin motherboard connector
and a PCIe connector are included even though they are not a part of the older
spec.
PHYSICAL BASICS
The casing of the Lion is a glossy, highly reflective, titanium colored finish. This is the kind of power supply
that computers marry while vacationing in Vegas: Showy, glitzy, and a bit
trashy (kind of like CES). The Lion should be right at home
in a pimped-out showpiece. Those of us without case windows… well, having
an well made-up power supply certainly can’t harm anything, can
it?
The Lion is 1.5″ longer than a standard power supply, with a small
cage extending out the back.
At 7″, the casing of the Lion is significantly longer than the usual 5.5″ for a standard
ATX power supply. The protective cage that hangs off
the rear of the power supply adds another inch, bringing the total length to
an unwieldy 8″. The cage contains a black heatsink that is meant to dissipate
heat into the air outside the case.
Two long vents run most of the length along the bottom.
The 80mm fan is located on the end of the casing. In a conventional case, the fan will
end up situated in the center of the case, which should cut down on direct
noise paths to the user. The fan grill is stamped but is still quite open, and
shouldn’t impede airflow too much.
There are also two long vents on the bottom that run most of the length of the
power supply. It’s not clear whether these are intended to be intakes, exhausts,
or both. Their exact function probably depends on the specific system it is
installed in. A system with a hot CPU may risk heating up the power supply,
since the CPU is typically located directly below the power supply. Allowing
air to flow through the bottom of the power supply provides could draw the waste
heat from the CPU through the power supply, heating it up in the process.
INSIDE THE LION
The interior of the Lion doesn’t look especially different from a fan-cooled
power supply. In fact, the heatsinks look identical to the ones in the
OCZ Modstream and the
Raidmax RX-520XPW, both of which are made by Topower.
Tightly packed components along the side. The two main capacitors get
their own heatsink.
The heatsinks are segmented to allow air to circulate through them.
The main heatsinks are a decent size.
An aluminum plate transfers heat from the internal heatsinks to the rear heatsink.
Note the vertical channels in the rear heatsink that allow heat to rise between
the fins.
Whatever extra cooling efficiency the Lion has comes from a small black plate
is screwed to the main heatsink.
The external heatsink has 112 individual fins.
The thermistor that is visible behind the grill was added for testing purposes, and
is not a part of the power supply.
The plate is connected to an external heatsink that hangs off the back of the
power supply. The heatsink, about the size of a standard 80mm fan, is divided
into 112 individual fins. The separation between the fins should prevent warm
air from being trapped under the fins.
By moving the heatsink
outside of the case, the effective ambient temperature for at least the external heatsink is room temperature,
not the temperature inside the computer case. The difference between room temperature
and case temperature is typically 10-15°C, so the difference is significant.
The cooling efficiency of the Lion will probably depend on how well the external heatsink
is coupled to the internal heatsinks, and how well it dissipates heat into the
surrounding air.
In addition to the external heatsink, the power switch and AC socket,
there is a mysterious unlabelled green button on the back of the Lion. It looks
tempting and inviting, but your ears will thank you if you leave it unpressed;
when depressed, the button bypasses the fan controller and runs the internal
fan at 12V. The resulting whine is so loud that it could be heard two rooms
away. There is also a bright blue LED that lights up when the button is pressed to
show that the power supply is working, just in case your ears don’t tell you.
The blue LED on the back lights up when the green button is pressed.
The fan is a high speed, sleeve bearing model from Power Cooler.
The fan in the Lion (Power Cooler PS802512H) is an odd choice for a quiet power
supply. First of all, the fan is a high speed model. Second, it uses sleeve bearings. In a
low speed fan, sleeve bearing fans often sound smoother than ball bearing fans,
but at higher speeds, turbulence noise masks the difference. Sleeve bearing
fans have lower heat tolerance, so a sleeve bearing fan seems like a very
strange choice for in a power supply where it only turns on at high temperatures.
The choice of fan does not inspire confidence that the Lion will last a long
time.
CABLES AND CONNECTORS
There are a total of ten cable sets.
- 20″ sleeved cable for main 20+4-pin ATX connector
- 23″ sleeved cable with 12V AUX connector
- 2 x 34″ cable with three 4-pin IDE drive connectors
and one floppy drive power connector - 23″ cable with two SATA drive connectors
- 14″ cable with an EMI shielded 6-pin PCIe connector
- 10″ cable with thermistor + mounting bracket
- 3 x 19″ cable with one FAN ONLY Molex connector and one three-pin fan
connector
Lots of unusual cables…
Special attention has been given to the PCIe cable, which is encased in a braided
metal sleeve to reduce electromagnetic interference (EMI). A ferrite ring around
the end of the connector helps reduce ripple. A second, more recent sample that
we received included a similarly shielded
cable with a single 4-pin IDE drive connector, presumably for use with
VGA cards that use this style of connector.
For most systems, this special attention to EMI and ripple is unwarranted.
Heavy overclockers may be able to squeeze a couple more megahertz out of their
processor, but the practical benefits of EMI shielding are minimal. They do
look cool though.
Three “Fan Only” cables come with a single Molex and three-pin
fan header each.
The three “Fan Only” cables are probably useful for more users the
the heavily shielded VGA power cables. Each cable comes with one Molex connector and
one three pin fan header. All of the “Fan Only” headers receive the
same source voltage, which is regulated according to the temperature measured
by a single thermistor that can be placed wherever the user chooses to put it.
Unlike the rest of the cables on the Lion, the cable for the thermistor is extremely
short. At 10″, it barely wraps halfway around the body of the power supply,
severely limiting the positioning of the thermistor.
The “Fan Only” voltage is controlled by this thermistor.
TEST RESULTS
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
the article SPCR’s PSU Test Platform V.3. It 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 well over 40°C at full power. This is impossible to achieve
with an open test bench setup.
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 get a pretty good overall
representation, but it is not quite the same as an extended meeting in person.
REAL SYSTEM POWER NEEDS: While our testing loads the PSU to full output
(even >600W!) 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 250W, 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 maximum power draw that an actual system can draw
under worst-case conditions. Our most power hungry Intel 670 (P4-3.8) processor
rig with nVidia 6800GT video card drew ~214W DC from the power supply under
full load well within the capabilities of any modern power supply. Please
follow the link above to see the details. It is true that very elaborate
systems with SLI could draw as much as another 100W, perhaps more, but the total
still remains well under 400W in extrapolations of our real world measurements.
SPCR’s high fidelity digital 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. 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 PSU 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.
On to the test results…
Ambient conditions during testing were 21°C and 19 dBA.
Although the Lion has only a single +12V rail rated at 28A, our test box uses
two separate +12V loads, which must be measured independently. The Lion was
therefore tested as though it had two 14A rails. Also, we did not test the -5V
output because it is no longer used by modern systems.
The thermistor that controls the “Fan Only” voltage was wedged next
to the thermistor measuring “Exhaust Temp”, so that a correlation
between temperature and voltage could be established.
| OUTPUT & EFFICIENCY: ePower Lion EP-450P5-L1 | ||||||||||||
DC Output Voltage (V) + Current (A) | Total DC Output | AC Input | Calculated Efficiency | |||||||||
| +12V1 | +12V2 | +5V | +3.3V | -12V | +5VSB | |||||||
| 12.05 | 0.95 | 12.06 | 1.71 | 5.19 | 1.01 | 3.33 | 0.96 | 0.1 | 0.2 | 42.7 | 59 | 72.4% |
| 12.17 | 0.96 | 12.16 | 1.73 | 5.17 | 3.91 | 3.34 | 2.76 | 0.1 | 0.4 | 65.4 | 86 | 76.0% |
| 12.13 | 2.85 | 12.13 | 1.72 | 5.16 | 4.78 | 3.34 | 1.81 | 0.2 | 0.5 | 91.0 | 116 | 78.5% |
| 12.16 | 3.88 | 12.14 | 3.29 | 5.15 | 7.55 | 3.34 | 4.61 | 0.3 | 0.8 | 149.0 | 187 | 79.7% |
| 12.15 | 4.80 | 12.12 | 4.97 | 5.16 | 10.31 | 3.35 | 6.31 | 0.4 | 1.1 | 203.2 | 258 | 78.8% |
| 12.16 | 5.73 | 12.12 | 6.46 | 5.15 | 12.02 | 3.33 | 8.36 | 0.6 | 1.4 | 251.9 | 325 | 77.5% |
| 12.17 | 7.83 | 12.13 | 6.47 | 5.13 | 15.35 | 3.29 | 10.06 | 0.7 | 1.7 | 302.5 | 399 | 75.8% |
| 12.16 | 11.64 | 12.13 | 9.64 | 5.04 | 23.8 | 3.24 | 14.91 | 1.0 | 2.5 | 451.2 | 640 | 70.5% |
| NOTE: The current and voltage for -12V and +5VSB | ||||||||||||
| OTHER DATA SUMMARY: ePower Lion EP-450P5-L1 | ||||||||
| DC Output (W) | 42.7 | 65.4 | 91.0 | 149.0 | 203.2 | 251.9 | 302.5 | 451.2 |
| Intake Temp (°C) | 24 | 25 | 27 | 33 | 35 | 39 | 41 | 44 |
| Exhaust Temp (°C) | 30 | 33 | 37 | 47 | 54 | 57 | 60 | 70 |
| Temp Rise (°C) | 6 | 8 | 10 | 14 | 19 | 18 | 19 | 26 |
| Internal Fan Voltage | 0.6 | 0.6 | 0.6 | 1.8 | 4.7 | 6.5 | 8.6 | 10.9 |
| Fan Header Voltage | 5.7 | 5.7 | 5.7 | 5.8 | 5.8 | 6.3-6.6 | 7.6 | 10.8 |
| SPL (dBA@1m) | * | * | * | * | 28 | 36 | 39 | 44 |
| Power Factor | 0.59 | 0.60 | 0.61 | 0.64 | 0.66 | 0.68 | 0.69 | 0.74 |
| NOTE: The ambient room temperature during testing *Fan was not spinning at this point, so the measured | ||||||||
ANALYSIS
1. VOLTAGE REGULATION
The individual voltage lines varied very little, but all three were a little
above their rated values. The +5V rail in particular was as much as 4% high
at one point. None of the lines went out of spec, and even at higher power
there was little in the way of voltage drop. Indeed, even at the highest output
power, the +12V rail stayed steady at approximately 1% above +12V and the +5V
rail only dropped marginally. Only the +3.3V rail showed any signs of struggling
with the load; it was the only rail that ever dropped below its rated voltage,
only at 300W output and above.
2. EFFICIENCY was quite good, peaking just shy of 80% at 150W output.
This is a good place for the peak efficiency, since it is close the the maximum
of power that most systems are likely to draw. Given its semi-fanless design,
efficiency is especially important for the Lion. Efficiency stayed in the upper
70’s through most of the output range, falling below 75% only at the highest
and lowest loads.
3. POWER FACTOR
The Lion does not have a power factor correction circuit, so power factor was
quite poor at lower loads. Power factor improved faster than usual as the power
load increased, and reached a high of 0.74 at full load.
4. TEMPERATURE AND COOLING
The thermal performance of the Lion was not good. Below 65W output, the temperature
rise stayed below 8°C, but almost doubled to 14°C by the time the output reached
150W. When the fan turned on at around 200W output, the difference between
the intake and exhaust temperatures was almost 20°C. When the power supply
was going full tilt (and the fan was on full blast), the temperature rise was
a scorching 26°C.
This is poor performance, even in comparison to other fanless power supplies.
For example, the Antec Phantom 500 only ever saw a rise of 14°C — and
this was at the lowest output; the internal cooling improved as the output power
increased.
5. FAN, FAN CONTROLLER and NOISE
The Lion actually contains two fan controllers: One which controls the internal
fan, turning it on only when absolutely necessary, and one which controls the
voltage received by the “Fan Only” cables.
With the fan off, the only noise produced by the Lion is a faint electrical
ticking that could not be reliably measured. Suffice to say that it would not
be easily heard when it is installed in an actual system.
Internal Fan: For low output loads, the internal fan received less than a volt.
The internal fan voltage did not even start to increase until
temperature at the external heatsink fins reached 45°C. The fan didn’t start spinning until it reached
50°C. In our test setup, this didn’t occur until the output reached
200W — above the sustainable output of most midrange systems, and close
to the maximum output drawn by any high-end gaming system.
However, the internal fan was noisy from the start, making a high pitched
whine even at minimum start speed (at 3V). The volume increased quickly even though the
voltage seemed to change fairly smoothly. At full
speed, it produced a real racket: 46 dBA@1m. Nevertheless, for many systems the
Lion will be effectively silent because the starting point of the fan is so
high.
The “Fan Only” output stayed at 5.7-5.8V until the thermistor
reached about 55°C. Many low and medium speed fans are very quiet
at this voltage, and the 55°C trigger point is high enough that the voltage
is unlikely to rise above this level very often. However, the voltage did not
rise steadily as the temperature rose. Especially when the temperature
was just above the trigger point, the voltage fluctuated quite a bit before
it stabilized, may translate into audible “revving” of
whatever fans are plugged into the Fan Only headers. Between 55°C and 70°C,
the relationship between temperature and voltage was fairly linear, with
small increases in temperature translating into corresponding increases in voltage. The “Fan Only” output is useful for quiet thermal control of fans, especially
in a low-heat system where the fans would ramp up.
| SAMPLE VARIANCE The first sample we received ran with its fan at full speed, regardless of output load and or the position of the “fan button”. The data in our tests comes from a second sample that |
| MP3 Sound Recordings of EP-450P5-L1
|
