be quiet! Dark Power Pro 430 power supply

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TESTING

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 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 provided above to see the details. It is true that very elaborate systems with the most power hungry video card today could draw as much as another 60~100W, but the total still remains well under 400W in extrapolations of our real world measurements. As for high end dual video card gaming rigs... well, to be realistic, they have no place in silent computing today.

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.

240V AC TEST SETUP

As mentioned earlier, some work had to be done to get 240V AC into the lab, along with test instrumentation that would give us AC data. The Kill-a-Watt and Seasonic Power Angel AC power meters work only on 120V AC with US/Canada AC jacks.

The room where the PSUs are tested used to be a spare kitchen. In fact, there is a 120/240V three phase AC outlet for an electric stove/oven directly behind the cabinet on which the PSU test loader rests. This dedicated outlet runs directly off two 15A/120V circuit breakers in the main electrical panel. This feature makes it ideal for use as a dedicated PSU test AC line. (Especially now that we have a 1,000W PSU awaiting testing in the wings: It will probably trip a 15A breaker if we try to get full output.) We obtained a power cord for use with this outlet, then ran the leads to two paired utility AC outlets, one pair for 240VAC and the other pair for 120VAC.


The dedicated heavy-duty 240VAC appliance outlet and plug. The standard Canada/US 120VAC plug is dwarfed in comparison.

The dedicated 240VAC and 120VAC outlets are only for PSU testing. The Extech 380803 Power Analyzer / Data logger in the background has no trouble with 240VAC, which is run through the unit. The LED display shows that 244VAC is at the input.

FINALLY, THE TEST RESULTS

Ambient conditions during testing were 21°C and 18 dBA. AC input was 244V, 60Hz.

OUTPUT & EFFICIENCY: Be Quiet! Dark Power Pro 430
DC Output Voltage (V) + Current (A)
Total DC Output
AC Input
Calculated Efficiency
+12V1
+12V2
+5V
+3.3V
-12V
+5VSB
12.03
0.94
12.02
1.70
5.10
0.95
3.38
0.95
0.1
0.2
42.0
62
67.7%
12.02
1.87
12.01
1.68
5.10
1.89
3.38
2.76
0.1
0.4
64.8
85
76.3%
12.01
1.84
12.01
3.19
5.10
2.77
3.38
3.62
0.2
0.5
91.7
119
77.0%
12.01
3.76
12.00
4.95
5.10
4.77
3.38
4.74
0.3
0.8
152.5
194
78.6%
12.00
5.60
12.00
6.60
5.10
5.65
3.35
4.65
0.4
1.2
201.6
248
81.3%
12.00
7.70
11.96
6.60
5.07
8.23
3.35
7.80
0.5
1.5
252.7
314
80.5%
11.95
8.60
11.96
9.64
5.08
8.23
3.37
7.80
0.6
1.8
302.4
374
80.8%
11.88
13.10
11.88
12.60
5.02
13.20
3.34
11.00
0.8
2.5
430.4
557
77.3%
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: Be Quiet! Dark Power Pro 430
DC Output (W)
42.1
64.8
91.7
152.5
201.6
252.7
302.4
430.4
Intake Temp (°C)
23
25
28
31
34
38
40
47
Exhaust Temp (°C)
25
26
30
34
38
45
46
55
Temp Rise (°C)
2
1
2
3
4
7
6
8
Fan Voltage (V)
4.3
4.3
4.6
5.3
6.3
7.0
7.8
9.7
SPL (dBA@1m)
21
21
22
24
26~27
30
32
35
Power Factor
0.85
0.90
0.97
0.98
0.98
0.98
0.98
0.98
AC Power in Standby: 0.9W / 0.04 PF
AC Power with No Load, PSU power On: 14.4W / 0.45 PF
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. LOW LOAD PERFORMANCE

Power consumption in standby mode was quite low, coming in at ~0.9W. Power factor was 0.04, which is difficult to understand. The power supply started properly with no load applied on the test bench, drawing a moderately high 14.4W at 0.45 PF. This suggests that the unit has built-in additional resistance to ensure low-current startup. Whether that additional load is dynamic is not clear, but the efficiency at higher loads is fairly good, so we suspect it is some kind of dynamic minimal loading.

2. VOLTAGE REGULATION was tops; none of the voltages fluctuated by more than +2.4% and -1.0%. Mostly they were dead on.

3. EFFICIENCY was very good compared to most PSUs we've tested, and about average for a recent ATX12V v2.2 power supply. The peak of 81.3% was reached at 200W and stayed above 80% until close to maximum output where it dipped a bit. At lower loads, efficiency was moderate, but reached 76.3% at 65W. Most systems require little more power than this at idle and tend to spend much of their time idling. This PSU would be fairly efficient under real world circumstances.

EFFICIENCY ADVANTAGE AT 240V AC

Because this unit is the first to be tested at 240VAC input, we wondered how much of an efficiency advantage it had compared to all the others we've tested with 120VAC input. To get some idea of the answer, we grabbed the nearest "free range input" power supply and tested it at a few selected power points, first at 120VAC, and then at 240VAC. The results on this early Antec NeoHE 430 are tabulated below.

Antec NeoHE 430 Efficiency at 120VAC and 240VAC
DC Output
120VAC input
240VAC input
Δ
Power
Efficiency
Power
Efficiency
66W
90W
73.3%
88W
75.0%
+1.7%
153W
189W
80.1%
183W
83.6%
+3.5%
253W
317W
79.8%
305W
83.0%
+3.2%
430W
574W
74.9%
545W
78.9%
+4.0%

The difference in power efficiency was smallest at low power and highest and high power. It ranged, for this sample, from a minimum of 2W or 1.7% at 66W output to a maximum of 29W or 4% at 430W output.

If this 2~4% efficiency advantage at 240VAC can be said to be typical, then the Be Quiet! test sample would have to be considered somewhat below average in efficiency for a high end PSU.

However, a 120/240 VAC comparison of efficiency on a single sample is hardly conclusive. We did try a few other full range AC input PSUs from Seasonic, Enhance and Enermax, and found very similar 2~4% differences. A more formal presentation of this issue and the corresponding test data will be presented in our next PSU test rig update, which will probably come in the next month or two.

4. POWER FACTOR was excellent thanks to the active power factor correction circuit, staying very close to the theoretical maximum of 1.0.

5. TEMPERATURE & COOLING

Cooling in the Be Quiet! was not a cause for concern. The temperature differential between in/out never rose above 8°C — a very good result. The temperature stayed modest in absolute terms. The 55°C exhaust temperature reached at the end of the test suggests good cooling.

As with many low speed fan PSUs, the Dark Power Pro should be considered only as a minor player in system cooling. Its fan is designed mostly to keep itself cool, not to provide ancillary cooling for other components in the system.

6. FAN, FAN CONTROLLER and NOISE

The quality of noise at turn-on was very good: Quiet, smooth and devoid of tonal or cyclical annoyances. The baseline SPL was about as low as we've recorded for any fan-cooled PSU at 21 dBA@1m.

The early promise continued as the load on the PSU was increased. The control circuit exhibited a smooth, slow-rising increase in fan speed/noise that puts it in a select group of the quietest PSUs. The 26~27 dBA reached at 200W output is not quite the equal of the most recent Seasonic S12 Energy Plus and M12 models (which remained at 21 dBA@1m even >250W), but it's roughly on par with earlier S12s and the Antec NeoHE, both of which are still extremely quiet. There's little question that this Be Quiet! DP Pro 430 is an impressively quiet power supply. It's too bad distribution is limited to 240VAC locales.

Power Supply SPL (in dBA@1m) Vs. Power Output
Model
65W
90W
150W
200W
250W
300W
400W
Be Quiet! DP Pro 430
21
22
24
26~27
30
32
35
Antec NeoHE 430
20
20
21
26
31
37
40
Seasonic S12-430
20
20
22
25
29
32
37
Seasonic S12 Energy Plus 550/650
20
20
20
20
21
25
38
Silverstone Element Plus ST50EF-Plus
23
23
23
25
34
41
43
Zalman ZM460-APS
22
23
26
29
31
34
37
Enermax Liberty EL500AWT/EL620AWT
21
21
24
30
35
38
41



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