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. That means a quieter 120mm fan can
be used, and less noise for your ears.
PCSTATS tests
power efficiency with the aid of an Extech Model 380803 Power Analyzer. The
meter is located between the mains 120AC supply and the power supply,
and a 120W dummy load is connected to the power supply being tested. Power jitter is
measured with a Mastech MS8230B Multimeter at the device power connectors. The
test apparatus and power meters are shown below.
The power supply looking device is
actually the 120W dummy load. To the right is a standard Voltmeter,
and in the background the Extech Model 380803 Power Analyzer (with readings for Watts,
PFC/KHz, source voltage (AC) and Amperage).
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. Voltages were read from the BIOS of an Foxconn Mars Intel P35
motherboard.
|
Power Jitter Observations
- Motherboard |
|
Listed Voltages |
Lower Voltage |
Upper Voltage |
Jitter |
|
+3.3V |
3.31V |
3.32V |
0.01V |
|
+5.0V |
4.9V |
4.94V |
0.04V |
|
+12V |
12.05V |
12.07V |
0.02V |
There
were next to no fluctuations in power when the S12D 850 was plugged in to the
motherboard, which speaks well for the PSU's use in systems that are built for tweaking or overclocking. Having
a stable input voltage from the power supply is critical if you're going to be
over-volting the processor or system components.
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 |
| Seasonic M12 700W |
700 W
(A-PFC) |
Active Power |
161W |
8W |
| Apparent Power |
165VA |
11VA |
| Corsair HX620W |
620 W
(A-PFC) |
Active Power |
171W |
8W |
| Apparent Power |
173VA |
12VA |
| Zalman
ZM600-HP |
600 W
(A-PFC) |
Active Power |
173W |
5W |
| Apparent Power |
175VA |
9VA |
| HEC Zephyr 650 |
650 W
(A-PFC) |
Active Power |
185W |
12W |
| Apparent Power |
190VA |
17VA |
| GlacialPower GP-PS550BP |
550 W |
Active Power |
178W |
6W |
| Apparent Power |
269VA |
17VA |
| Cooler Master Real Power Pro 750W
|
750 W
(A-PFC) |
Active Power |
158W |
6W |
| Apparent
Power |
163VA |
9VA |
| Seasonic S12 II
500W
|
500W
(A-PFC) |
Active Power |
145W |
7W |
| Apparent
Power |
148VA |
10VA |
| Enermax Infiniti
720W |
720W
(A-PFC) |
Active Power |
179 W |
12 W |
| Apparent Power |
181 VA |
18 VA |
| COOLMAX GREEN
POWER CUQ-1200B |
1200W
(A-PFC) |
Active Power |
172 W |
9 W |
| Apparent Power |
193 VA |
12 VA |
| PC Power &
Cooling Silencer
750 Quad |
750
(A-PFC) |
Active Power |
168 W |
12 W |
| Apparent Power |
175 VA |
15 VA |
| Enermax Galaxy
EGX850EWL |
850 W
(A-PFC) |
Active Power |
184 W |
11 W |
| Apparent Power |
193 VA |
16 VA |
| Seasonic M12D
750
|
750W
(A-PFC) |
Active Power |
169W |
7W |
| Apparent
Power |
173VA |
9VA |
 Seasonic S12D
850 |
850W
(A-PFC) |
Active Power |
148W |
7W |
| Apparent Power |
149VA |
10VA |
|
The Seasonic S12D 850 power supply draws 148W
of power when a 120W load was hooked up, which is 81.1% efficiency, in line
with its 80 Plus efficiency rating! Considering the high power capacity of this
unit, the efficiency with only a 15% load is very promising.
If the amount of load was ramped up closer to the 850W capacity of the S12D 850,
we'd be seeing even greater efficiency here, likely approaching the 90% mark.
RSS Newsletter
