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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
SPCR's PSU Test Platform
V.3. 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.
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 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 65W 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 powerful 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 provided 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 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.
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 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 19dBA, 119~121V/60Hz.
|
OUTPUT & EFFICIENCY: SilverStone Strider 560W
|
|
DC Output Voltage (V) + Current (A)
|
Total DC Output
|
AC Input
|
Calculated Efficiency
|
|
+12V1
|
+12V2
|
+5V
|
+3.3V
|
-12V
|
+5VSB
|
|
12.20
|
0.96
|
12.19
|
1.73
|
5.07
|
0.98
|
3.38
|
0.97
|
0.0
|
0.1
|
41.5
|
59.4
|
69.9%
|
|
12.21
|
1.91
|
12.20
|
1.73
|
5.06
|
1.93
|
3.37
|
2.80
|
0.1
|
0.2
|
65.8
|
87.4
|
75.3%
|
|
12.21
|
1.90
|
12.19
|
3.30
|
5.06
|
2.87
|
3.35
|
2.76
|
0.1
|
0.3
|
89.9
|
114.6
|
78.4%
|
|
12.17
|
3.80
|
12.15
|
5.00
|
5.05
|
4.66
|
3.35
|
4.64
|
0.1
|
0.5
|
149.8
|
185.7
|
80.7%
|
|
12.15
|
6.61
|
12.14
|
4.99
|
5.04
|
6.42
|
3.34
|
6.25
|
0.2
|
0.7
|
200.0
|
242
|
82.7%
|
|
12.14
|
7.75
|
12.12
|
6.48
|
5.04
|
8.15
|
3.32
|
8.41
|
0.2
|
0.9
|
248.5
|
304
|
81.7%
|
|
12.12
|
8.70
|
12.10
|
8.12
|
5.02
|
10.71
|
3.30
|
10.04
|
0.3
|
1.1
|
299.7
|
372
|
80.6%
|
|
12.07
|
11.39
|
12.04
|
11.22
|
5.04
|
13.90
|
3.30
|
14.18
|
0.4
|
1.4
|
401.1
|
516
|
77.7%
|
|
12.06
|
14.12
|
12.01
|
14.24
|
5.05
|
17.12
|
3.29
|
17.22
|
0.5
|
1.8
|
499.4
|
665
|
75.1%
|
|
12.08
|
15.98
|
12.00
|
15.73
|
5.01
|
19.35
|
3.28
|
19.32
|
0.5
|
2.0
|
558.1
|
765
|
73.0%
|
|
NOTE: The current and voltage for -12V and +5VSB lines
is 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.
|
|
OTHER DATA SUMMARY: SilverStone Strider 560W
|
|
DC Output (W)
|
41.5
|
65.8
|
89.9
|
149.8
|
200.0
|
248.5
|
299.7
|
401.1
|
499.4
|
558.1
|
|
Intake Temp (°C)
|
21
|
22
|
25
|
28
|
29
|
29
|
30
|
34
|
38
|
41
|
|
Exhaust Temp (°C)
|
26
|
30
|
32
|
37
|
40
|
42
|
45
|
51
|
56
|
61
|
|
Temp Rise (°C)
|
5
|
8
|
7
|
9
|
11
|
13
|
15
|
17
|
18
|
20
|
| Fan Voltage (V) |
4.7
|
4.7
|
4.8
|
4.8
|
5.6
|
7.3
|
9.2
|
12.0
|
12.0
|
12.0
|
| SPL (dBA@1m) |
24
|
24
|
24
|
24
|
28
|
36
|
40
|
44
|
44
|
44
|
|
Power Factor
|
0.98
|
0.99
|
0.99
|
0.99
|
0.97
|
0.98
|
0.98
|
0.99
|
0.99
|
0.99
|
|
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. VOLTAGE REGULATION was very good, staying within ±2% on the
+12V and +5V rails and ±3% on the +3.3V rail. Voltages were closest to
nominal at full load, and only the +3.3V rail ever dropped below nominal. This result helps supports Silverstone's claim for EPS12V support.
2. EFFICIENCY
The efficiency curve of the Strider was very steep ranging from 70% at 40W,
up to 83% at 200W, and back down to 73% at full load. Overall, the efficiency
is quite good, but there's no question that it's best in the middle. Fortunately,
the peak efficiency is reached where it matters most: In the 200-300W range
where most high performance desktops draw peak power.
83% peak efficiency is top-tier performance; SilverStone is right to brag
about the efficiency of the Strider. However, their
claim of 80% efficiency at full load could not be confirmed; our sample fell to 73% efficiency at 560W. Given the very steep drop in efficiency
after the peak, the tough thermal conditions of our testing
procedure may have caused efficiency to drop more than it would in a test where the intake
is fixed at a lower temperature.
To put this in perspective, several other power supplies with top-tier efficiency
were compared for minimum efficiency, maximum efficiency, and efficiency at full
load.
|
Highly Efficient Power Supplies (Ranked by Maximum Efficiency)
|
|
Model
|
Minimum
Efficiency
|
Maximum
Efficiency
|
Efficiency
@ Full Load
|
|
Seasonic SS-400HT 80 Plus
|
77%@40W
|
85%@150W
|
83%
|
|
FSP Zen 300W
|
77%@40W
|
85%@150W
|
83%
|
|
SilverStone Strider 560W
|
70%@40W
|
83%@200W
|
73%
|
|
Antec Phantom 500W
|
75%@40W
|
83%@250W
|
78%
|
|
Seasonic S12 430W
|
76%@430W
|
82%@200W
|
76%
|
As the table shows, the Strider is tied for the third most efficient power
supply we've tested when sorted by peak efficiency. However, its minimum
efficiency and efficiency at full load are well below the other units on the
leaderboard .
3. POWER FACTOR may have been the best we've ever seen. Even at the
low output of 40W, the power factor was 0.98. There was no curve
to speak of, power factor remained at 0.98 throughout testing.
4. TEMPERATURE AND COOLING
Thermal performance was good enough though most of the lower output range,
but showed signs of struggle as the power output increased. The thermal rise
between intake and exhaust never really stabilized, and hit a whopping 20°C
at full load. By this load, the fan had been spinning at full speed for some
time. It seems likely that the increase in temperature may have contributed
to the large drop in efficiency seen above 400W. In comparison, most of the other PSUs we've tested at this load have shown a thermal rise of 10~15°C.
It's difficult to know exactly why the thermal rise was so high, but here are some possibilities.
- The heatsink surface area is too small to dissipate the excess heat.
- The airflow is not effective enough to evacuate all the heat.
- The density of the components creates too high an impedance for effective airflow.
- All of the above.
However, even with the high temperature at full load, none of the voltage lines
showed signs of instability. At this point, the intake temperature was 41°C. Given the tolerance of our thermal measurements, the Strider was at its 40°C rated maxiumum operating temperature.
5. FAN, FAN CONTROLLER and NOISE
The basic noise character of the fan was not bad, but it spun too fast to
be considered quiet compared to most of the competition. The default noise was a
smooth purr that blended easily into the background in spite of its volume.
At faster speeds, the noise was also quite smooth, but it quickly became too
loud.
One trait marred the overall smoothness of the sound. There was an odd,
pure overtone that could be clearly heard when the fan voltage was between 5.3~5.4V.
Outside of this voltage range, no resonant tone could be heard. This tone was
probably unique to our particular test setup, but other systems may have other
resonant tones.
The fan spun at minimum speed until the internal temperature rise was ~10°C,
when it began to spin up sharply. The rate of increase was quite fast, but did
not vary too much. Changes in fan speed were clearly noticeable, but once the
fan found its new speed it tended to stay there until the next large change
in temperature.
Perhaps because it was spinning so fast to begin with, the fan did not ramp
up until relatively late in the test: The first measurement point above minimum
was 200W, which is above the maximum power potential of all but a high-end or
gaming system.
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