Seasonic Super Silencer 400 - ATX12V 1.3

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TEST RESULTS

Measurements were made at 5 output power levels: 65W, 90W, 150W, 300W and 400W. The PSU was allowed to run for ~10 minutes at each power level before measurements were recorded. The room temperature was 24C.

Table A. Load on the PSU*

+12V
24
36
60
144
168
+5V
20
20
45
80
145
+3.3V
16.5
26.4
39
69
81
-12V
2.4
3.6
3.6
3.6
3.6
+5VSR
2
4
2
2
2
TOTAL
65W
90W
150W
300W
400W

*The absence of the -5V line is not an error; the ATX12V v1.3 PSU Design Guide eliminates the need for this line. The load on each line was carefully readjusted to ensure the correct total power delivered.

Table B. On test bench, 24C ambient temperature

DC Power
65W
90W
150W
300W
400W
AC Power
89W
120W
195W
385W
527W
Internal Heat*
24W
30W
45W
85W
127W
Efficiency
73%
75%
77%
78%
76%
Power Factor
0.98
0.98
0.99
0.99
0.99
Fan Voltage
4.17
4.17V
4.2V
7.25V
11.5V
dBA @ 1 m
22
22
23
34
44
Exhaust Temp
27C
28C
29C
31C
33C

*The difference between AC input and DC output is lost as internal heat in the PSU.

Table C. In-case thermal simulation , over light bulb, with case fan turned off

DC Power
65W
90W
150W
300W
400W
Light bulb
60W
60W
100W
100W
100W
Case Temp
30C
30C
32C
34C
35C
Exhaust Temp
31C
33C
38C
41C
43C
Fan Voltage
4.17
4.17V
4.29V
7.8V
11.5V
dBA @ 1 m
22
22
23
35
44

ANALYSIS

1. EFFICIENCY was the very best ever encountered. Even at the low 65W load level where most PSUs fail to reach 65%, the Super Silencer started off smartly at an amazing 73%, climbing to 75% at 90W and 77% at 150W. The claimed 78% was reached at 300W output. Even at full output, it was still a high 76%. The efficiency of the Super Silencer 400 betters every other PSU tested at SPCR by a big margin.

These efficiency calculations are not errors, inadvertent or otherwise. All the load tests were repeated 3 times on two sample units. With the AC line voltage at 119V~120V, the results on all the tests fell in a range of less than 1% variance. The reported data is from a single set of tests on one of the samples.

The most practical result of this high efficiency is that the PSU runs cooler at every output power level compared to other models. The tables below illustrate it plainly. (The data on "other" models was taken from published SPCR reviews of real PSUs. These other PSUs were not named because there is no need to single them out for criticism; against the Super Silencer, all other PSUs' efficiency performance suffers.) The last column titled "% heat / waste" shows the percentage of increase in heat or energy wasted compared to Seasonic Super Silencer 400.

400W DC Output
AC Power
efficiency
heat
% heat / waste*
Super Silencer 400
520W
76%
127W
-
other 400
560W
71%
160W
26%
other 400
569W
70%
169W
33%
*
300W DC Output
AC Power
efficiency
heat
% heat / waste*
Super Silencer 400
385W
78%
85W
-
other 400W
410W
73%
110W
29%
other 400W
416W
72%
116W
36%
other 300W
420W
71%
120W
41%
*
65W DC Output
AC Power
efficiency
heat
% heat / waste*
Super Silencer 400
90W
72%
25W
-
other 400W
104W
62.5%
39W
56%
other 400W
98W
66%
33W
32%
other 300W
97W
67%
32W
28%

OK, enough about efficiency already...

2. VOLTAGE REGULATION was excellent, within -/+2% on all lines in any combination of loads tried (somewhat at random). It was often within -/+1%. The low and high voltage seen on each of the main lines is shown:

  • +12V: 12.02 to 12.26
  • +5V: 4.9 to 5.09
  • +3.3V: 3.33 to 3.4

It should be noted that I have no way of testing line regulation, so AC conditions are steady-state, not dynamic as it would be (potentially) in a real PC; I have no way to vary input AC voltage at this time. The AC line voltage in the lab as measured by the Kill-a-Watt power meter is usually within a couple of volts of 120V.

3. POWER FACTOR was 0.98~0.99 at all power levels. Just about as good as can be. This may help you save money on your electric bill. In combination with the knowledge about the Super Silencer's high efficiency, ownership could evoke in you a heady sense of environmental righteousness.

4. NOISE was very low on startup. The sonic quality of the SuperRed fan has a a touch of bearing buzz. It is a fairly quiet fan, but not a Panaflo 80L (our reference quiet fan). At the 4.17V start and low load / temp fan voltage it is very quiet. No electronic noises such as coil whine or buzzing was heard at any time during the testing.

Noise measurements were made in the live test room in the evening. With all equipment turned off in the 23C temp room, the ambient noise was measured at ~17 dBA. The 22 dBA @ 1 meter measured on startup remained steady till the 150W load was reached, at which point the fan speed seemed to turn a corner and start to rise. The fan controller seems to have a clear "step" at 7~7.25V. That is, beyond a certain temp / load, the fan sped up from the low <4.2V level and kept climbing till 7~7.25V was reached. This fan voltage was first reached at ~300W output, at which point the measured noise was 34 dBA @ 1 meter.

The 22 dBA measured at low-med load is 3-4 dBA quieter than the Seasonic SS-300FS-APFC tested last year, which used an Adda fan*; it measured ~26 dBA in a quick check under the same conditions above. A similar quick check showed the Nexus NX3000 low-load noise to be about 20 dBA @ 1 meter.

*Seasonic Electronics USA informed us that the SuperRed fan has now replaced the Adda in the SS-xxxFS-APFC series, so its noise level should be similar to the Super series (except for the added turbulence of the earlier series' stamped-metal grill at higher fan speeds ).

5. COOLING: The high efficiency of the Super Silencer 400 allowed it to remain cool even in the tough in-case thermal simulation with a 100W bulb. Table B details the results, which are self-explanatory: It is the coolest running PSU yet encountered, and in a real system, running a system without any case fan could be a very viable option with the Super Silencer.

Usually, using the thermal speed controlled fan in the PSU as the only heat exhaust causes the fan to speed up as the PSU heats up, thereby adding back the noise removed with the case fans. The in-case thermal simulation results suggests this is not likely to happen with the Super Silencer, at least not with loads up to ~150W or more. Even at the 300W power level there was only a marginal increase in fan voltage and noise with the in-case thermal simulation.

A final comment on load testing:

Full power testing of PSUs for any length of time is a very demanding test, generally tougher than what real use conditions can demand. SPCR's bench testing is steady-state and can be extended indefinitely until the PSU burns; in real world applications, PSUs in PCs don't get this kind of abuse except maybe in a server room, which is a different application altogether, and the power demand on them varies up and down in a much more dynamic way, with average power loads rarely exceeding 150W for desktop PCs.



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