The price of energy is increasing world wide, so any
reduction in the amount of power a computer draws is a welcome change in our books. Power supplies
which employ Power Factor Correction (PFC, or A-PFC) help ensure efficient conversion of AC to
DC voltage, and reduce the amount of energy wasted as heat.
The following power supply tests were all conducted with an Extech Model 380803 Power
Analyzer located between the mains 120AC supply and the power supply, and with
a 120W dummy load. Power jitter is measured with a Mastech
MS8230B Multimeter at the device power connectors. The test apparatus and power meters
are shown below.
Here is a picture of the test set up which we will use
to evaluate the Seasonic S12 Energy Plus SS-650HT 650W power supply. The power supply looking device
is actually a 120W dummy load.
Power Jitter Observations -
Motherboard |
|
Voltage jitter is read by
accessing the power options displayed in the motherboard BIOS, with the system obviously in an unloaded state. *All voltages
were read from the BIOS of an ECS RS480-M motherboard.
|
Power Jitter Observations
- Motherboard |
|
Listed Voltages |
Lower Voltage |
Upper Voltage |
Jitter |
|
+3.3V |
3.25V |
3.33V |
0.08V |
|
+5.0V |
4.96V |
4.98V |
0.02V |
|
+12V |
11.8V |
11.95V |
0.15V |
|
-12V |
11.99V |
11.99V |
0V |
|
-5.0V |
5.00V |
5.00V |
0V |
|
+5.0Vsb |
5.00V |
5.00V |
0V |
The
voltage rails fluctuate slightly although it's nothing
to be alarmed at. Even at the lowest voltages, the
power supply still has plenty
to go around and will not sacrifice system stability. Voltage levels are all pretty close the
mark.
| Power Jitter Observations
- Multi-meter |
|
Voltage jitter was read by a Mastech MS8230B Multimeter with the system in an
unloaded state. During testing the power supply is was still connected to a full
computer and voltage values.
|
Power Jitter Observations
- Multi-Meter |
|
Listed Voltages |
Lower Voltage |
Upper Voltage |
Jitter |
|
+3.3V |
3.3V |
3.3V |
0V |
|
+5.0V |
5.0V |
5.0V |
0V |
|
+12V |
11.99V |
11.99V |
0V |
It's
interesting to see here that the digital multimeter
is reporting much better values than we see from the BIOS. The
12V rail is hovering
just a notch under 12V which is great to see. Next, load tests with the Seasonic 120W PSU tester and then our final conclusions on this unit.
When looking at the Seasonic Power Supply test results we see two values, wattage
and volt-amps. Since it might not be clear what they measure, here's a brief
overview.
The
volt-amp (VA) value is how much real power is being consumed by the power supply
being tested to provide the wattage (W) value. The higher the VA value is, the
more electricity is being used by the power supply. Because no electrical device
is 100% efficient, there will always be some loss when converting AC to DC. The
closer the volt-amps and wattage figures are to each other, the more efficient a
power supply is. This is called the Power Factor: wattage / volt-amps =
PF.
Since we're testing with a 120W dummy load, the
load on the power supply (wattage) should be as close to this figure as
possible. Anything above this load in apparent power describes the overhead and
wasted energy (given off as heat) for the particular power supply being tested.
For the unloaded tests, the wattage and volt-amp figures should be as close as
possible to one another. The lower the figures are, the less power is being
wasted.
Measurements were taken with an Extech 380803 Power Analyzer.
| Seasonic Power Load Tests |
| Power Supply Model |
Wattage |
Test Type |
Loaded |
Unloaded |
| Seasonic SuperTornado |
400 W
(A-PFC) |
Active Power |
177 W |
6 W |
| Apparent
Power |
182 VA |
7 VA |
| Vantec iON2 |
350 W |
Active Power |
192 W |
10
W |
| Apparent Power |
277 VA |
21 VA |
| Antec TruePower 330 |
330 W |
Active Power |
195 W |
22 W |
| Apparent Power |
289 VA |
38 VA |
| Ultra
X-Connect Green UV 500W |
500 W |
Active Power |
193W |
22 W |
| Apparent Power |
307 VA |
40 VA |
| AOpen Silent Power AO400-12AHN |
400 W |
Active Power |
179W |
9 W |
| Apparent Power |
275 VA |
18 VA |
| Seasonic S12-430 |
430 W
(A-PFC) |
Active Power |
179W |
6W |
| Apparent Power |
180VA |
9VA |
| PC Power and Cooling Turbo-Cool 510 Express/SLI |
510 W
(A-PFC) |
Active Power |
200 W
|
29 W
|
| Apparent Power |
202 VA |
32 VA |
| HEC
Ace Power 580UB |
580 W |
Active Power |
183 W
|
12 W
|
| Apparent Power |
272 VA |
26 VA |
| HEC
Win 550UB |
550 W |
Active Power |
184W |
10W |
| Apparent Power |
263VA |
22VA |
| Akasa
PowerPlus AK-P550FF |
550 W
(A-PFC) |
Active Power |
194W |
38W |
| Apparent Power |
197VA |
40VA |
| AOpen
Prima Power AO700-12ALN |
700 W
(A-PFC) |
Active Power |
172W |
3W |
| Apparent Power |
181VA |
9VA |
| PC
Power & Cooling Turbo-Cool 1KW |
1000 W
(A-PFC) |
Active Power |
205W |
25W |
| Apparent Power |
207VA |
32VA |
| Seasonic S12 600 |
600 W
(A-PFC) |
Active Power |
164W |
7W |
| Apparent Power |
173VA |
9VA |
| Mushkin Enhanced XP-650 |
650 W |
Active Power |
192W |
22W |
| Apparent Power |
279VA |
43VA |
 Seasonic S12 Energy Plus
SS-650HT |
650
W
(A-PFC) |
Active Power |
150W |
7W |
| Apparent
Power |
150VA |
10VA |
|
With a
120W dummy load, the Seasonic S12 Energy Plus SS-650HT 650W reaches 80% efficiency.
The high efficiency of
the Seasonic S12 Energy Plus SS-650HT means that you will have a
lower overall
electricity bill
in the long term. Thus far, it is the most efficient power supply to pass through the PCSTATS labs, and
the first of what I hope will be many 80 PLUS power supplies to
come. Active power under load rests at 150W, and just 7W when unloaded.
Apparent Power under load rests at just 150Volt-Amps, 10VA when unloaded.
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