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Nexus Value 430 PSU: Affordable Silence

March 13, 2009 by Mike
Chin

Product
Nexus Value 430

430W ATX12V v2.2 Power Supply
Manufacturer
Nexus
Sample Supplier
End PC Noise
Market Price
US$80

It's a sign of the times that a 430W power supply seems an anomaly. Retail PSU power ratings have gone through the roof over the last couple of years that even at SPCR, most of the models reviewed recently have been well over 500W. While there's some merit to the idea that extreme gaming systems actually need a kilowatt of electricity, the stronger driving force behind the power buildup is profit. There's simply more money to be made in higher rated PSUs.

The Nexus Value 430 power supply isn't just a lower power model. It's also smaller, modest looking rather than flashy, and priced well under $100. It strikes one as a return to sanity and normality — before SLI and Crossfire multiple graphics cards gaming came along.

Nexus is a pioneer in quiet computing components based in the Netherlands. The company has been active in bringing quiet computing components and products to the market long before the concept became a fashionable buzzword. The Nexus brand fans, for example, are still among the few reference fans we use in our reviews.



A nearly plain 2-ink cardboard box.



Interior packaging is just as plain. A bit more shock damping might be preferred.



FEATURE HIGHLIGHTS

Nexus Value 430 Feature Highlights (from the Nexus web site)
FEATURE & BRIEF OUR COMMENT
Smaller, 125mm deep - more space inside your pc for more/better airlflow.
There's some merit in this point. The norm is 140~165mm deep.
ATX12V?
Version not specified; current is V2.2.
A minimum of 80% efficiency guaranteed at all loads But it is not 80 Plus certified — not that it has to be for the PSU to be >80% efficient.
Sleeved cables The norm these days.
Real silent performance with less then 15.0 dB(A) in idle mode Of course, we'll be trying to verify this claim... and to see what happens at higher loads.
4 x 12V Rails In a 430W PSU? What for??
Full range automatic VAC input Common for Active PFC power supplies.
UL, CSA, DVE, FCC, CE and CB approved Safety standards; the more the merrier.
Complies to WEEE & RoHS environment directives Required in the EU these days.

EXTERNAL TOUR

The Value 430 sports a grey finish and no bling. A 120mm fan draws air into
the power supply from the internals of the system. The main exhaust vent is the
rear, where the honey-comb grill offers low resistance. There a long row of slot vents on the cable output side, presumably to assist in cooling. This will be seen by some silent/cooling PC enthusiasts as a negative, as some of the heat from the PSU will be forced into the PC case, and possible increase the internal temperature for the computer components. A simple wire grill protects the fan from cables or prying fingers while
providing a low resistance to the airflow.



A standard 120mm fan PSU: We like the complete absence of flash.



These vents will force some of the heat from the PSU into the PC case.

Nexus Value 430 Specifications


The label on the PSU tells much of what we want to know.


Four 12V lines are listed on the specifications, but it's highly unlikely that they are really separate; they may have a 20A limiter on each "line", but this is also unlikely, because there are no instructions about which connectors are part of which "line".

There is no UL file number on the label to check at the UL
Online Certifications Directory
so there's no easy way to tell who is the power supply manufacturer. We could tear the thing apart and look for tell-tale signs on the printed circuit board and other components, but most readers don't really care; the main issue is electrical and acoustic performance.

OUTPUT CABLES

The Nexus Value 430 comes with a healthy lineup of outputs.

  • 1 - 21" cable w/ ATX 20+4-pin motherboard connector
  • 1 - 18" cable w/ Aux 12V 4+4-pin connector
  • 1 - 21" cable w/ 6+2-pin PCI-Express connector
  • 1 - 21" cable w/ 6-pin PCI-Express connector
  • 2 - 29" cable w/ 2x SATA connectors
  • 1 - 33" cable w/ 3x 4-pin Molex and 1x floppy connector
  • 1 - 27" cable w/ 3x 4-pin Molex connectors

INTERIOR

The components are laid out on a reasonably tidy PCB that fills the available space. The heatsinks are quite small, and the primary capacitor has a standard 85°C rating. There isn't
much obstruction to airflow.



Conventional layout.



The primary capacitor is a 450V 220uF Teapo rated at 85°C.






A secondary PCB appears to sport trim pots, used usually to tweak output voltages.

These have become rare on modern PSUs.

The 120x25mm fan, rated for 0.18A at 12V, is from a company called Muhua Industrial. The L12S at the end of its model number suggests it is a low speed fan (obvious from the low current rating), with a sleeve bearing. Note that sleeve bearings are not supposed to last as long or work as quietly when the fan is facing downward. However, the actual rotational speed has a significant impact on both longevity and noise. If it spins slowly, the bearing will not be subject to much wear, and it shouldn't make much noise.



Muhua Industrial low speed sleeve bearing 120x25mm fan.

TESTING

For a fuller understanding of ATX power supplies, please read
the reference article Power
Supply Fundamentals
. 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 V4.1
. The testing system is a close simulation of
a moderate airflow mid-tower PC optimized for low noise.

Acoustic measurements are now performed in our anechoic chamber with ambient level of 11 dBA or lower, with a PC-based spectrum analyzer comprised of SpectraPLUS software with ACO Pacific microphone and M-Audio digital audio interfaces.



PSU test rig in anechoic chamber.

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 over 1000W.
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.

The 120mm fan responsible for "case airflow" is deliberately
run at a steady low level (6~7V) when the system is run at "low"
loads. When the test loads become greater, the 120mm fan is turned up to a higher
speed, but one that doesn't affect the noise level of the overall system. Anyone
who is running a system that draws ~400W or more would definitely want more than
20CFM of airflow through their case, and at this point, cooling is the main concern, not the noise level.

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 we test the PSU to full
output 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 40W and 300W, 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 power draw of several actual systems
under idle and worst-case conditions.
Our most power-hungry overclocked
130W TDP processor rig with an ATI Radeon X1950XTX-512 graphics card drew ~256W
DC peak 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 dual
video cards today might draw as much as another 150~200W, but the total should
remain under 500W in extrapolations of our real world measurements.

INTERPRETING TEMPERATURE DATA

It important to keep in mind that PSU 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.

TEST RESULTS

Ambient conditions during testing were 20°C and 10 dBA. AC input was 121V,
60Hz.

OUTPUT & EFFICIENCY: Nexus Value

DC Output Voltage (V) + Current (A)

Total DC Output

AC Input

Calculated Efficiency
+12V1
+12V2
+5V
+3.3V
-12V
+5VSB
12.23
0.97
12.23
-
5.00
0.96
3.43
0.97
0.1
0.1
21.7
35
62.0%
12.20
0.97
12.20
1.72
5.00
0.96
3.43
0.93
0.1
0.2
43.0
60
71.7%
12.18
1.87
12.18
1.72
5.14
1.94
3.41
2.68
0.1
0.4
65.8
86
76.5%
12.18
3.68
12.18
1.72
5.08
2.85
3.38
1.83
0.2
0.5
91.2
113
80.7%
12.17
3.69
12.17
4.94
5.08
4.46
3.37
4.58
0.3
0.8
150.2
183
82.1%
12.13
6.42
12.13
4.94
5.01
6.07
3.35
5.88
0.5
1.1
199.2
238
83.7%
12.12
7.55
12.12
6.59
4.92
7.93
3.33
7.22
0.5
1.5
248.4
300
82.8%
12.09
8.56
12.09
9.46
4.81
8.79
3.32
7.89
0.6
1.7
303.5
367
82.7%
12.08
11.06
12.08
12.20
4.78
12.03
3.27
11.77
0.6
2.3
397.5
499
79.7%
12.08
12.76
12.08
12.60
4.81
12.54
3.27
12.15
0.8
2.5
429.9
540
79.6%
Crossload Test
11.80
12.16
11.80
12.72
5.15
0.97
3.40
0.96
0.1
0.1
303.5
365
83.2%
+12V Ripple: 58mV max @ 430W

+5V Ripple: 22mV max @ 430W

+3.3V Ripple: 27mV max @ 430W
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

OTHER DATA: Nexus Value 430
DC Output (W)
22
43
66
91
150
199
248
303
398
430
Intake (°C)
20
22
24
25
30
32
32
34
39
40
Exhaust (°C)
23
25
28
30
34
36
37
44
53
55
Temp Rise (°C)
3
3
4
5
4
4
5
10
14
15
Fan* (RPM)
370
370
370
370
370
670
740
740
760
760
SPL ([email protected])
11
11
11
11
11
16
18
18
19
19
Power Factor
0.63
0.78
0.90
0.95
0.96
0.96
0.96
0.97
0.97
0.97

AC Power in Standby: 0.4W

AC Power with mininum load (1A on 3.3V, 0.1A on 5VSB): 12.5W / 0.62 PF

* No fan voltage could be measured because the controller in this PSU apparently uses PWM control, which means the output is always 12V. The RPM was monitored using a calibrated strobe. How PWM is implemented with a 2-wire fan is not clear; all WPM fans we've seen thus far are equipped with 4 wires.

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 v2.2 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. It allows reduced cooling airflow, which translates
to lower noise.

Efficiency was as specified, over 80% from >20% of rated power, despite the lack of 80 Plus certification. Below 90W, it fell as expected, but no more than normal. The broad peak of >82% was reached at 150~300W, with a maximum of 83.7% at 200W. This is a good peak point for a 430W PSU. Surprisingly, the efficiency held up quite well even to full output, straying just a bit under 80%. This is significant because the operating environment temperature was quite high, and the internal temperature of the PSU would have been considerably higher yet. More on that later.

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%. All the voltage lines were quite stable, especially the 12V line, which started a touch high and never dropped below 12V even at full load.

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 100s of kHz). 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. The results here will not win contests but they were perfectly modest, well within requirements.

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 a smaller, cheaper
UPS backup; they are priced according to their VA (volt-ampere) rating.

PF was relatively low at low loads, and it did not reach the >0.95 typical of Active PFC power supplies until 90W load. It never went above 0.97. For all practical purposes, unless you're running a very low power system, the difference between this and higher PF power supplies will be extremely difficult to assess.

5. LOW LOAD PERFORMANCE is significant mainly to minimize energy waste and with system that demand very low power; the latter can cause some PSUs not to start. Standby performance good with just 0.4W draw. The unit does not start with no load. The minimum load needed to start was 1A on 3.3V, and 0.1A on 5VSB. At this low load, there was a bit of hissing and hum from the PSU, both of which dissiappeared when the 5VSB load was increased to 0.3A and some load on the 12V line was applied. In actual use, the PSU will never see such a low load.

6. CROSSLOAD TEST - Basically the load on the 12V line was maximized while the load on all the other lines was minimized. The effect was a 0.2V drop on the 12V line and slightly raised voltages on the 5V and 3.3V lines. There were no other changes.

7. LOW & 240 VAC INPUT

The power supply was set to 300W load with 120VAC through the
hefty variac in the lab. The variac was then dialed 10V lower every 5 minutes.
This is to check the stability of the PSU under brownout conditions where the
AC line voltage drops from the 110~120V norm. The Value 430 is rated for
operation 100VAC ~ 240VAC 50/60 Hz Most power supplies achieve higher efficiency
with higher AC input voltage. SPCR's lab is equipped with a 240VAC line, which
was used to check power supply efficiency for the benefit of those who live
in 240VAC mains regions.

Various VAC Inputs: Value 430 @ 300W Output
VAC
AC Power
Efficiency
244V
352W
85.2%
120V
363W
82.6%
110V
368W
81.5%
100V
372W
80.6%

Efficiency improved by 2.6% with 244VAC input at this load. The sample passed the 100VAC minimum input without any issues. Neither voltage regulation nor ripple changed appreciably
during the test.

7. NOISE and FAN CONTROL

The noise level during the pre-test warmup with 65W load was so low as to require a double-take. Was the PSU really on? Was the fan spinning? Up very close, a tiny bit of ticking and hum could be heard. The fan was indeed spinning, and a check with the calibrated strobe light showed it to be at 370RPM. This is the slowest of any fan in a PSU we've yet reviewed.

The sound level was measured to be about 11 [email protected], or a single decibel above the ~10 dBA noise floor of the anechoic chamber. The microphone picked it up from a meter away, but I could not hear it from a meter. I had to get within about a foot. Ditto Larry, who was also in the lab at the time of testing. This incredibly low noise level prevailed from 20W to above 150W load.

At 200W the SPL rose to a still barely audible 16 [email protected] The fan speed was measured to be 670RPM. The overall noise character was smooth, mostly broadband, a bit of hum, and barely audible ticking. The noise level went up incrementally to 18 [email protected] at 250W load, then to 19 dBA at full power.



The difference with the PSU on at idle was barely one decibel.



The ambient curve looks different (from previous graph) because the vertical scale has been expanded. Still well under 20 [email protected] even at 430W load.

These results were so surprisingly low that the microphone and SpectraPlus acoustic analysis system was recalibrated for accuracy twice, and the load test was repeated two more times at full load. The results were nearly identical every time.

8. COOLING

Throughout the course of the load testing — over three hours during which time the PSU was always on with the load steadily increasing to the rated output — I was concerned that the slow spinning fan would cause overheating in the PSU. Surprisingly, my concern was unfounded; the temperature rise through the unit remained under 5°C up to 250W load, and it reached a relatively modest 15°C at full power. Of couse, the total heat being generated in the PSU itself was only a touch over 100W.

The 10°C rise seen at 300W is probably the most relevant measurement: This PSU is not likely to be used in systems that draw any more than 300W. The single cooling fan in the test loader box was running at ~750 RPM at that load. It appears that the combination of good efficiency and minimal fan speed in both the PSU and the case will be enough to keep the PSU adequately cooled.

The question of how much heat is pushed into the PC case (or test, box in this case) via the slots on the output side of the Value 430 was not possible to answer. The internal temperature in the test box was not any higher than with other PSUs at the same test loads, so if there is any effect , it seems very small. In a real system run for long periods, an optical drive directly in front of the PSU may get hotter than normal. The simple solution would be to leave the top optical drive bay empty and perhaps set it up as a vent.

NOTE: It is possible that the very low airflow of the Value 430 fan actually helps it achieve lower temperature rise numbers. Heat is generated in the test box, but because the airflow in the box is always low, it may not move up into the PSU that easily. Perhaps the slow speed of the PSU fan means it draws less of the test box heat into itself than a faster spinning fan might.

MP3 SOUND RECORDINGS

These recordings were made as 24-bit / 88 kHz WAV files with a high
resolution, lab quality, digital recording system
inside SPCR's
own anechoic chamber
(11 dBA ambient), then converted to LAME 128kbps
encoded MP3s. We've listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn't hear it from
one meter, chances are we couldn't record it either!

Each recording starts with 6~10 seconds of room ambient, followed
by 10 seconds of the product's noise. For the most realistic results,
set the volume so that the starting ambient level is just barely audible, then
don't change the volume setting again while comparing all the sound files.

Sound Recordings of PSU Comparatives
in the Anechoic Chamber

CONCLUSIONS

The Nexus Value 430 makes a bold leap to the very top of our quiet PSU rankings. It is the quietest fan-cooled PSU we've yet tested, by a 2-3 decibel margin, the closest being the Enermax Modu 82+ 425W at around 13 dBA, the Seasonic M12D-850W at 14 dBA and the Antec Signature 650 at 15 dBA. At such vanishingly quiet levels, this is no mean feat. That it is achieved by a modest, unassuming product with a name like Value 430 is even more surprising, especially when you consider that the other top contenders are high end models from giants in the power supply field. It even begs the question of why you'd pay big bucks for a fanless PSU of similar power rating.

The maximum SPL of 19 [email protected] is, again, amazingly quiet. It bests the very quietest competitors at ~400W load by a fairly big margin, something like 5~8 dBA. Despite the the relatively modest 15°C temperature rise thorugh the PSU, one can't help thinking that such low airflow must surely shorten its useful life. On the other hand, most system with which this PSU will be used will not draw anything near its rated power at any time. Keep the power draw to under 300W, and you'll probably be quite safe. With the pace of change in computer technology, it's likely the PC will be considered obsolete before the PSU fails.

Electrically, while the Value 430 is not exceptional (compared to the high-tech, pricier competition), it is no slouch. Our sample had no obvious weaknesses. Don't ask of it what it cannot deliver, and it should provide fine power delivery for most midrange systems.

For the card-carrying, faithful SPCR party member, this Nexus has to be something of an affirmation. Most PC enthusiasts do not run dual-video card behemoths that demand a kilowatt. Even with a high performance graphics card, a typical modern dual/quad core CPU system with lots of RAM and a couple of hard drives will not demand more power than the Value 430 can deliver. (See the idle and full load power demand of various systems profiled on page four of Power Supply Fundamentals.) For the noise, energy and value conscious power user, it's a perfect balance: Virtual silence, low enough energy use, adequate power, and a very friendly $80 price tag.

* * *

Our thanks to End PC Noise for the Nexus Value 430 sample.



The Nexus Value 430 is Recommended by SPCR.

* * *

SPCR Articles of Related Interest:

Power Supply Fundamentals

SPCR PSU Test Rig V.4

Seasonic S12 Energy Plus 550 and 660

Seasonic M12D-850


NX-8060 PSU improved: Nexus redux


Silverstone ST45NF: 450W Fanless Power Supply

SilverStone Decathlon DA700 power supply


Modu82+ 625 Power Supply: Enermax to the Forefront


Corsair HX520 & HX620

* * *

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