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Nexus NX-8060 ATX power supply

May 29, 2007 by Mike
Chin

Product
Nexus NX8060

600W ATX12V v2.2 Power Supply
Manufacturer
Nexus
Sample Supplier
End PC Noise
Market Price
~US$150

Nexus is a specialist in quiet computing components based in the Netherlands. Over the years, they've done a good job of sourcing the right suppliers to bring quiet products to this marketplace. The Nexus brand fans, for example, are among the very few reference fans we use in our reviews. Nexus is also one of the pioneers of quiet computer power supplies, along with Seasonic and a couple of other names which now seem to have passed into history. In SPCR's early days, the Nexus NX-3000 was the quietest off-the-shelf PSU and reigned atop the silent hill for quite a long time. Surprisingly, their last couple of models (notably the NX-9003) seemed a bit dated against a wave of modern, high efficiency competitors.

The newly introduced NX-8000 series look to be a major advancement. Over 80% efficiency is claimed, and all three models in the series have modular cabling with interfaces for a wide variety of modern PC components. Naturally, very low noise is specified.

The NX-8060 under review is a 600W model at the top of the series. The main difference between it and the others in the line appears to be the power rating: 500W for the NX-8050 and 400W for the NX-8040. The three units do have slightly different SPL ratings; the NX-8060 is rated at ~ 1 and ~2 [email protected] higher than the other models at idle. Regardless, at 19.6 dBA (idle) the NX-8060 promises to be very quiet indeed.



The boxes are also much changed from the white and yellow cubes of yesteryear.



Plain black finish, minimum bling and a big bundle of cables.

 

FEATURE HIGHLIGHTS

Nexus NX-8060 Feature Highlights (from the Nexus web site)
FEATURE & BRIEF COMMENT
Meets ATX 12V Version 2.2 Specifications
The current industry
standard for ATX power supplies.
80-plus; a minimum of 80% efficiency guaranteed at all loads! The standard already set by many PSUs we've tested. It's not clear whether Nexus is referring to the US certification program; the PSU does not have the identifying 80 Plus sticker and Nexus is not listed among certified manufacturers.
Modular, sleeved cables Not unusual, and nice for cable management. The connectors look sturdy, and the different types of ends may help with good current distribution.
Real silent performance with just 19.6 dB(A) in idle mode Of course, we'll be trying to verify this claim... and to see what happens at higher loads.
Enough cables and connectors for any high-end system Agreed.
Full range automatic VAC input Fairly 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 NX-8060 sports a simple black finish and a nice lack of 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 grill offers low resistance. There are two small slot vents, one on the side and another on the cable output side, presumably to assist in cooling particular hot components. A simple wire grill protects the fan from cables or prying fingers while
providing a low resistance to the airflow. It also comes with a big bundle of modular cables.



An almost stereotypical 120mm fan PSU design: We like the absence of flash.



Six output jacks in three distinct groups; they may help current load distribution.

Nexus NX-8060 Specifications

Four 12V lines are listed on the specifications, but it's highly unlikely that they are really separate; they may have an 18A limiter on each "line", but this is also unlikely, because there are no instructions about which connectors are part of which "line".

Checking the UL file number on the label at the UL
Online Certifications Directory
tells us that the power supply is built
by Fortron Source Power Group Inc (FSP), a prolific Taiwanese power supply manufacturer that has supplied all previous Nexus PSU models. Going back to the 80 Plus list of certified power supplies and manufacturers, FSP currently has 12 certified production models, including one 400W model and two 600W models. It could be that the Nexus NX-8060 is a rebadged version of these certified models, but the absence of 80 Plus labeling or links at the Nexus site to 80 Plus suggests otherwise.

OUTPUT CABLES



Three output cables are attached; the rest are modular; all are sleeved.

The NX-8060 comes with a healthy lineup of cable connectors. Here are the attached cables:

  • 20" cable w/ ATX 20+4-pin motherboard connector
  • 20" cable w/ Aux 12V 4+4-pin connector
  • 20" cable w/ 6-pin PCI-Express connector

The detachable cables:

  • 1 - 31" cable w/ 3 x 4-pin Molex connectors
  • 2 - 31" cable w/ 2 x 4-pin Molex and 1 x floppy connector
  • 2 - 31" cable w/ 3 x SATA connectors
  • 1 - 19" cable w/ 6-pin PCI-Express connector; an additional one for dual video card systems.
  • 1 - 19" cable w/ Aux 12V 4+4-pin connector; an additional one... for?

INTERIOR

The components are laid out reasonably tidily on a main PCB that's surprisingly small. The heatsinks are also quite small, and the primary capacitor has a standard 85°C rating. There isn't
much obstruction to airflow, which is good.

The fan is one of Adda's, which has become popular among quiet PSU makers. It's from the same series used in Seasonic and Corsair PSUs, for example. The fan is soldered directly to terminals on the main PCB.



Equipped with one the the popular Adda 120mm fans.

Marked as a medium speed, ball bearing model.



Output jacks are on a secondary PCB.




All the wiring is direct soldered; heatsinks are small.

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.4.1
. The testing system is a close simulation of a moderate airflow
mid-tower PC optimized for low noise.



The current incarnation of SPCR's PSU test system.

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 well beyond 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. Its measured SPL is <20 [email protected] 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, the noise level of the
exhaust fan is typically not the greatest concern. This fan is turned off whenever noise measurements or recordings are made.

While great effort has been made to devise as realistic an operating
environment for the PSU as possible, the 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 1.1 kW!) 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 50W and 250W, because it is the power
range where most systems work 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, overclocked Intel Pentium D950 Presler dual-core processor
rig with ATI X1950-XTX video card drew 256W 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 possible that very elaborate
systems with the most power hungry components overclocked to the limits could draw a bit more power, but the total would still remain well under 400W. As for high end, dual video card gaming rigs... well,
they have no place in quiet 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 one meter from the exhaust
vent at a 45° angle, outside the airflow turbulence area. We also recorded at 30cm distance when the sound was difficult to hear from 1m. All other noise sources in the
room were turned off while recording.

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.

TEST RESULTS

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

OUTPUT & EFFICIENCY: Nexus NX8060

DC Output Voltage (V) + Current (A)

Total DC Output

AC Input

Calculated Efficiency
+12V1
+12V2
+5V
+3.3V
-12V
+5VSB
12.12
0.97
12.12
1.72
5.15
1.01
3.35
0.96
0.1
0.2
43.0
62
69.0%
12.09
1.89
12.09
1.72
5.13
1.99
3.35
0.96
0.1
0.3
62.6
85
73.5%
12.07
1.89
12.08
3.27
5.14
1.98
3.35
0.96
0.1
0.4
89.0
115
77.4%
12.08
3.82
12.08
4.99
5.08
4.63
3.32
1.80
0.2
0.6
150.4
186
80.8%
12.08
5.65
12.06
6.45
5.08
4.60
3.30
4.60
0.3
0.8
201.3
241
83.5%
12.06
8.43
12.06
6.45
5.01
8.67
3.30
6.26
0.3
1.0
249.6
300
83.2%
12.06
8.43
12.06
9.43
4.92
9.80
3.30
8.30
0.3
1.2
296.1
356
83.2%
12.06
13.08
12.06
12.95
4.81
14.60
3.28
14.83
0.6
1.9
449.2
548
82.0%
12.01
14.75
12.01
20.7
4.78
19.35
3.28
19.06
08
2.5
599.7
756
79.3%
Crossload Test
12.01
12.60
11.98
33.6
4.91
0.97
3.32
0.95
0.1
0.2
558.2
699
79.8%
+12V Ripple: 18.9mV max @600W

+5V Ripple: 11.1mV max @ 600W

+3.3V Ripple: 8.4mV max @ 600W
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 SUMMARY: Nexus NX8060
DC Output (W)
43.0
62.6
89.0
150.4
201.3
249.6
296.1
449.2
599.7
Intake (°C)
25
26
26
29
29
30
31
35
38
Exhaust (°C)
30
31
31
36
39
40
42
51
62
Temp Rise (°C)
5
5
5
7
10
10
11
16
24
Fan Voltage (V)
4.3
4.6
5.0
5.8
6.4
7.1
7.3
10.5
11.5
SPL ([email protected])
21
24
26
27
29
32
33
38
42
Power Factor
0.82
0.91
0.97
0.98
0.99
0.99
1.00
1.00
1.00

AC Power in Standby: 0.3W

AC Power with No Load, PSU power On: 8.3W / 0.62 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 was very good. At 40W~65W, it was fairly typical of recent high efficiency PSUs rated at >500W, starting low but climbing fast. The 80% mark was reached somewhere between 90W and 150W output.

If we are to consider this PSU as being 80 Plus certified, then it must be 80% efficient or better at 20%, 50% and 100% of rated output. To give Nexus the benefit of a doubt, we can accept that 80% efficiency could have been reached at the 120W mark, which is 20% of the rated 600W output.
The peak of >83% was reached around 200W, and it stayed at this level up to near 400W, where it began dropping off. It just fell shy of 80% at full load, but it missed by less than a percentage point, which is probably beyond the accuracy resolution of our test system. At 240VAC input, the efficiency rose slightly by a maximum of about 2% at the peak.

2. VOLTAGE REGULATION was excellent under all loads. All the voltage lines were extremely stable, especially the 12V line, which barely drooped even at full load.

3. RIPPLE was modest, well within requirements.

4. POWER FACTOR was excellent at all loads. It was a little low at very low loads, but quickly rose to near the theoretical best.

5. LOW LOAD PERFORMANCE

Standby and no-load performance were both excellent, with no load coming in
at under 10W. The NX-8060 had no trouble starting with no load.

6. LOW AC VOLTAGE PERFORMANCE

Low VAC Test: NX-8060 @ 450W Output
VAC
AC Current
AC Power
Efficiency
120V
5.08A
548W
82.0%
110V
5.53A
553W
81.4%
100V
6.12A
557W
80.8%
90V
6.92A
565W
79.4%
80V
6.92A
576W
78.1%

The NX-8060 was hardly affected by low AC voltage inputs, even down to 80VAC at 75% of rated output; it's only rated for operation at 100~240VAC. Ripple stayed well within
limits and voltages were stable at all times. The unit should have no trouble dealing with brownouts.

7. TEMPERATURE & COOLING

Up to around 300W, the NX-8060 kept itself reasonably cool, with a temperature rise of 5~11°C. By 450W output, the temperature rise reached 16°C, and at full load, it went up to 24°C. Our PC system simulation thermal box feeds all of the heat of the PSU's output through the box, just like in a real system, so that we can see how the PSU's fan and cooling system would behave in a real system. Neither of these temperatures are of any real concern, as there was no indication of overheating causing performance deterioration (usually, output power and/or voltage reduction over time).

8. FAN, FAN CONTROLLER and NOISE

The starting speed of the fan was approximately 3.8V. The measured sound pressure level was just under 20 [email protected], as Nexus claims. However, even at 40W load, the fan ramped up a bit almost immediately and kept climbing until it stabilized at 4.3V, where the noise measured 21 dBA. At the fairly typical system idle power load of 65W, the fan had sped up enough to the point where it measured a clearly audible 24 dBA. The sound quality was smooth, as expected of this familiar fan.

Nexus gives details about its acoustic testing in a 3 x 3 x 2 meter anechoic chamber, and this transparency is very admirable. But the test is conducted with the PSU in the open and the ambient temperature is not given. On the basis of our testing, the ambient temperature had to be no higher than our 21°C, and the PSU "idle" noise was measured in the open whie running at near-zero load. It's the only way that "19.6 dBA at idle" could be claimed.

Nexus also shows a graph showing a slow rise in sound pressure level as the load is increased. Again, this must be showing the performance in open air at a modest ambient temperature, because the slope noise increase is much shallower than our findings.



Graph of noise / load from Nexus; the ambient temperature is probably constant, at normal room level.

In our thermally realistic test, the fan speed / noise rose linearly in accordance with increases in heat / load. The fan voltage and noise rose steadily, and by a modest 150W load, it reached 5.8V and 27 [email protected] At 250W load, the noise reached 32 dBA, which is beyond our ">30 [email protected] is not quiet" limit. In the graph below, you can compare our data with that from the Nexus graph.

The graph above dramatically illustrates the difference between testing a PSU's noise / power at room temperature in open air... versus actual operation inside a real PC (which our thermal test box simulates closely). What SPCR's test shows is that in a normal PC environment where the PSU will be subject to at least some of the heat from other components, the noise of the NX-8060 will not be much of a factor at idle and low loads; ambient room noise, and noises from other components will tend to merge together. Above ~150W load, however, the PSU will become an increasingly audible source of noise. It is a good candidate for use in the Antec P180/P182 case where the PSU is thermally isolated in its own cooling zone. (Note: We noticed no ramping up of noise from the Nexus NX-8060 when it was used in a recent review of the AntecP182.)

MP3 SOUND RECORDINGS

Each of these recording have 6 seconds of silence to let you hear the ambient
sound of the room, followed by 10 seconds of the product's noise.

Sound Recordings of PSU Comparatives

HOW TO LISTEN & COMPARE

These recordings were made
with a high resolution, studio quality, digital recording system, 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. Two recordings of each noise level were made, one from a
distance of one meter, and another from one foot
away.

The one meter recording
is intended to give you an idea of how the subject of this review sound
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. For best results, set your volume control so that the
ambient noise is just barely audible. 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!

The one foot recording is
designed to bring out the fine details of the noise. Use this recording
with caution! Although more detailed, it may not represent how the subject
sounds in actual use. It is best to listen to this recording after you
have listened to the one meter recording.

More details about how
we make these recordings can be found in our short article: Audio
Recording Methods Revised
.

 

CONCLUSIONS

The NX-8060 brings
Nexus up to date with the modern competition of high power, 12V-centered, high efficiency power supplies. The NX-8060 has plenty of power for quiet PCs, an excellent cable management system, excellent voltage regulation, high power factor, universal VAC input, and
high ability to deal with low AC voltage conditions (brownouts). The efficiency is very good, component
quality looks decent, and the choice of fan is apropos. In a nutshell, the NX-8060 passes all the power and electrical aspects of performance with flying colors.

Where the unit doesn't quite meet expectations is in the area of acoustics. In the last couple of years, the very best quiet PSUs have achieved a high level of competence. They are not only quiet at idle, but stay extremely quiet even to >200W loads in rising ambient temperatures, which means that they will stay quiet in most systems almost all the time. These include the models listed under Sound Recordings of PSU Comparatives above, and a handful of other models in the Recommended PSUs article. The NX-8060 doesn't quite make it into this select group, because its noise-to-power (or temperature) curve is too linear and too steep: It gets too noisy at too low a load and keeps getting louder as the load is increased. In this regard, the NX-8060 shows its heritage clearly: Almost all the FSP-source PSUs we've tested have similarly linear noise-to-power curves.

In a typical PC built with quiet components, the NX-8060 will probably remain unobtrusive until pressed with demanding applications, especially in hot weather. The intelligent choice of a smooth sounding fan helps quite a bit. To keep the fan from speeding up, this Nexus requires that it's not exposed to too much heat.

We've written often in the past that most systems don't demand anywhere near what many video card manufacturers (and others in the industry) recommend. The various systems profiled on page four of Power Supply Fundamentals were measured to idle at 54W~109W, and to peak under extreme load at 102W~256W DC power demand. (The most powerful of these systems was a "serious gaming rig".) The quiet-seeking PC builder would be well advised to employ the NX-8060 with a system that would demand less than 100W at idle, and preferably, less than 150W at peak. Otherwise, some way of ensuring cooler intake air to the PSU is necessary. If the occasional sally into >30 [email protected] noise won't be bothersome, then this adivice can be safely ignored.

Our overall assessment: The Nexus NX-8060 is a solid, modern, high performance PSU well worthy of consideration. Its acoustic are basically good, but they are bettered by the best.

* * *

Our thanks to End PC Noise for the Nexus NX-8060 sample.



* * *

SPCR Articles of Related Interest:

Power Supply Fundamentals

Power Distribution within Six PCs

SPCR PSU Test Rig V.4

Seasonic S12 Energy Plus 550 and 660

Silverstone Element Plus ST50EF-Plus

Zalman ZM600 heatpipe-cooled modular PSU

Seasonic M12-700

Corsair HX520 & HX620

* * *

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