Modu82+ 625 Power Supply: Enermax to the Forefront

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TEST RESULTS

Ambient conditions during testing were 21°C and 18~20 dBA. AC input was 118~121V, 60Hz.

OUTPUT, VOLTAGE REGULATION & EFFICIENCY: Enermax Modu82+ 625
DC Output Voltage (V) + Current (A)
Total DC Output
AC Input
Calculated Efficiency
+12V1
+12V2
+5V
+3.3V
-12V
+5VSB
12.26
0.98
5.16
0.99
3.36
0.95
0.1
21
31.5
66.1%
12.26
0.98
12.26
1.72
5.16
0.99
3.36
0.95
0.1
0.1
43
55
78.4%
12.24
1.89
12.24
1.72
5.16
1.98
3.36
2.64
0.1
0.3
66
82.5
80.0%
12.23
1.86
12.24
3.41
5.13
2.89
3.29
2.56
0.1
0.3
91
112
80.9%
12.21
4.68
12.21
4.92
5.12
3.75
3.31
2.52
0.2
0.4
149
177
84.3%
12.16
5.56
12.16
6.54
5.12
5.56
3.30
5.26
0.4
0.8
202
235
85.9%
12.14
6.62
12.14
7.95
5.10
7.36
3.30
7.23
0.4
1.0
248
287
86.4%
12.09
8.60
12.09
9.63
5.06
8.27
3.29
8.48
0.4
1.2
301
352
85.4%
12.06
11.26
12.06
12.67
5.05
11.65
3.29
12.40
0.5
1.6
401
478
83.8%
11.95
12.79
11.95
14.50
5.03
15.58
3.28
14.40
0.6
2.0
497
608
81.7%
11.90
20.60
11.90
16.63
5.00
18.43
3.28
17.93
0.8
2.5
625
790
79.1%
Crossload Test*
11.90
24.42
11.90
24.30
5.11
0.98
3.34
0.95
0.1
0.1
590
717
82.3%
+12V Ripple (peak-to-peak): 22mV @ 90W, rising to a max of 63mV @ full load
+5V Ripple (peak-to-peak): 20mV@ 90W, rising to a max of 34mV @ full load
+3.3V Ripple (peak-to-peak): 20mV@ 90W, rising to a max of 24mV @ full load
Maximum +12V Ripple during the Crossload Test was 82mV.
*For the crossload test, the 12V line is maximized, and the +5V and +3.3V lines are set to just 1A.

NOTE:
The current and voltage for -12V and +5VSB lines are 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: Enermax Modu82+ 625
Output (W)
21
43
66
91
149
202
252
301
401
497
625
Intake (°C)
22
23
25
27
32
33
33
33
40
41
44
Exhaust (°C)
26
27
32
34
39
42
43
43
48
50
56
Temp Rise (°C)
4
5
7
7
7
9
10
10
8
9
12
Fan RPM
490
490
506
510
512
600
720
860
1180
1730
1780
SPL (dBA@1m)
19
19
19
19
19
20
21
22
26
36
37
Power Factor
0.92
0.94
0.98
0.98
0.98
0.98
0.99
0.99
0.99
0.99
0.99
AC Power in Standby: 2.3W / 0.38 PF
AC Power with No Load, PSU power On: 8.9W / 0.8.4 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. EFFICIENCY — This is a measure of AC-to-DC conversion efficiency. The ATX12V Power Supply Design Guide recommends 80% efficiency or better at all output power loads. 80% efficiency means that to deliver 80W DC output, a PSU draws 100W AC input, and 20W is lost as heat within the PSU. Higher efficiency is preferred for reduced energy consumption and cooler operation. The latter allows reduced cooling airflow, which translates to lower noise.

With its claim of 88% efficiency at 230VAC input, we knew the Modu82+ would be efficient. Our test sample reached >86% efficiency even with 120VAC input at ~250W output, and as you'll see below, reached 89% efficiency with 240VAC input. This is very impressive performance, not quite matched even by the most efficient PSUs we've tested. At the lower end with 120VAC input, it hit 66% at 21W, 78% at 43W, and 80% at 66W, which are excellent results. Bear in mind that many modern systems spend most of their time idling within this modest range.

Note that the the measured efficiency dropped below 82% at 500W load, and below 80% at 625W load. Does this contradict the report from 80 Plus which shows >82% efficiency at full power? No, not really. The 80 Plus testing procedure does not take thermal conditions into consideration; the PSUs are tested in typical room temperature, most often 20~25°C. Our testing does not coddle the PSUs in this way; the ambient working temperature of the PSU rises with the power load, as would be the case in a real system. The Enermax is rated for full power operation up to 40°C. The intake temperatures in the test environment at 500W and 625W loads were 41°C and 44°C, respectively; it's no surprise that the efficiency dropped a bit.

2. VOLTAGE REGULATION refers to how stable the output voltages are under various load conditions. The ATX12V Power Supply Design Guide calls for the +12, +5V and +3.3V lines to be maintain within ±5%. The Modu82+ 625 had excellent VR, staying within +2% and -1% on the important 12V line though all the tests, even the extreme crossload test. It was similar on the +5V and +3.3V lines.

3. AC RIPPLE refers to unwanted "noise" artifacts in the DC output of a switching power supply. It's usually very high in frequency (in the order of kilohertz or megahertz). The peak-to-peak value is measured. The ATX12V Guide allows up to 120mV (peak-to-peak) of AC ripple on the +12V line and 50mV on the +5V and +3.3V lines. Ripple on the Modu82+ was quite modest on all the voltage lines, well within the ATX12V specification.

4. POWER FACTOR is ideal when it measures 1.0. In the most practical sense, PF is a measure of how "difficult" it is for the electric utility to deliver the AC power into your power supply. High PF reduces the AC current draw, which reduces stress on the electric wiring in your home (and elsewhere up the line). It also means you can do with smaller, cheaper UPS backup; they are priced according to their VA (volt-ampere) rating. PF on this sample was close to perfect across all loads, as is the norm for most power supplies with active PF correction circuitry. It wasn't quite perfect at the very low end, with a ratio of 0.92 at 20W, but this is a lower load than the MODU+ 625 will ever realistically face.

5. AC INPUT VOLTAGE TESTS

LOW VAC INPUT: This is to check the stability of the PSU under brownout conditions where the AC line voltage drops from the 110~120V norm. The Modu82+ is rated for 100VAC minimum input; it was pushed down to 90VAC without any problems. DC output voltage regulation remained unchanged from that achieved at 120VAC.

LOW VAC TEST: Enermax Modu82+ 625 @ 500W load
VAC
AC Power Input
Efficiency
120
612W
81.70%
110
619W
80.78%
100
625W
80.00%
90
632W
79.11%

EFFICIENCY WITH 240 VAC INPUT: Most power supplies achieve higher efficiency with higher AC input voltage. SPCR's lab is equipped with a 240VAC line, used to check power supply efficiency for the benefit of those who live in 240VAC mains regions. The 240VAC efficiency advantage measured nearly 4 percentage points higher at 500W load, but it dropped to under 3 percentage points at 250W output. At lower loads, it will drop further, probably to about 2 percentage points.

DC Output
240VAC Input
120VAC Input
Power
Efficiency
Power
Efficiency
250W
280W
89.3%
289W
86.5%
300W
340W
88.2%
350W
85.7%
500W
585W
85.5%
612W
81.7%

6. LOW LOAD TESTING revealed no problems starting at low loads. The power draw at standby was a modest 2.3W, and power consumption with no load was good at 8.9W.

7. FAN, FAN CONTROLLER and NOISE

There's no doubt about it: We have a new quiet champ. This Modu82+ sample's acoustics upon turn-on were so low that I had to take a close look to make sure the fan was actually spinning. Never mind the earlier comments about double ball bearings or clear plastic blades; this fan is clearly the quietest we've ever heard in a stock power supply — well, close to NOT heard. The measured SPL of 19 dBA@1m was just a single decibel higher than the 18 dBA ambient of the room. During the day, I could not clearly hear the PSU fan from a meter away, but the SLM could.

This SPL measurement was actually made at about one o'clock in the morning. The ~20 dBA typical ambient in the lab during the day was too high to get clear readings. Also, every other electrical device in the room had to be unplugged or turned off: Every wallwart, power brick, and even the CFL lights — in order to eliminate all other low level buzzing or humming sounds to isolate the PSU's contribution to the SPL from a meter away.

From about six inches away, the acoustic signature was primarily a mild electrical buzz, audible over a very soft touch of broadband noise from the fan. It was hard to believe that the fan was even spinning, but the telltale flow of air could be felt on my hand. I can only conjecture how exactly Enermax managed to obtain such a smooth, soft noise from their seemingly ordinary fan. Perhaps their implementation of PWM control is perfectly matched to this fan. At the ~500RPM start level (they say 450RPM), it's at least as quiet as any fan I've listened to. That says a lot; I've played with and listened closely to literally hundreds of fans over the years.

Amazingly, the fan stayed at the same barely audible level all the way to around 200W ouput when it made its first small step up to 600RPM and 20 dBA@1m. Even at 300W output, the fan was still spinning only at 720RPM, with a measured SPL of just 22 dBA@1m. At 400W load, the fan had spun up only to around 1200RPM, and the SPL measured just 26 dBA@1m. It was a smooth broadband sound. Beyond that level, the fan ramped up quickly, as expected, peaking out at 37 dBA beyond 500W.

Comparison: PSU Noise (in dBA@1m) Vs. Power Output
Model
65W
90W
150W
200W
250W
300W
400W
500W
Enermax Modu82+ 625W
19
19
19
20
21
22
26
36
Corsair HX520/620
22
22
22
22
22
22
29
43
Seasonic S12 Energy+ 650
20
20
20
20
21
25
38
38
Corsair VX450
21
21
21
21
22
26
44
-
Seasonic M12II-430
21
21
21
24
28
35
41
-
Seasonic S12II-380
21
21
21
21
25
31
39
-
Zalman ZM460-APS
22
23
26
29
31
34
37
37
Enermax Liberty 500/620
21
21
24
30
35
38
41
41

The table above shows measured noise-to-power data from selected reviewed PSUs. The green cells are all the values that are 30 dBA or higher; <30 dBA@1m or lower is SPCR's SPL definition of "quiet". The data shows clearly that the Modu82+ starts at a lower noise level and stays quieter than any other PSU all the way to 500W (and beyond). The differences at the lower power levels are small, but they will be audible if your ambient threshold noise is low enough. At the higher power levels, the Modu82+ acoustic advantage increases significantly against most other PSUs.

CAUTION: Please keep in mind that the above results cannot be considered absolutely "correct". It tells about PSU samples in our test rig. The thermal fan control employed in every one of these power supplies interacts with the working environment, which means in that different environments (read systems: case, components, configuration, etc.), the results are bound to vary.

8. TEMPERATURE & COOLING

The Modu82+ 625W displayed an unusually low temperature rise throughout the load testing. The temperature rise was held to under 10°C until 250W load. As the fan sped up in response to increasing heat, the temperature rise dropped again into single digit numbers over 300W, till beyond 500W. However, it's also important to know that the actual temperature (not the temperature difference) inside the PSU load tester was higher at a given power load level than with many other PSUs. This is a direct result of the slower spinning fan used in the Modu82+, which suggests that the PSU should not be relied to provide any cooling for the system other than itself. Similar comments can be made for some of the other quiet PSUs at the top of our recommended PSU list, such as the Seasonic S12 550 / 650 Plus and the Corsair HX series.

The temperatures reached during full load power test (44°C in, 56°C out), along with the drop in efficiency to below 80% tells us that at such high power loads, your system would do well to have better cooling than our PSU load tester. However, sustaining such a high power load is no easy task outside a lab test setting, with a real computer. For an analysis of real PC power needs, please check the section Real System Power Requirements in our reference Power Supply Fundamentals article.

AN ASIDE: Three 12V lines? The Modu82+ is said to have three 12V lines each capable of delivering a maximum of 25A and a combined (simultaneous) total of 50A. This means it has three current limiters on three bundles of 12V wires, with each limiter set to 25A. However, it's not clear which wires being together in each bundle. We did not trigger any 12V/25A limiters during our testing.



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