Cougar GX-700: 80 Plus Gold from a new brand

A German affiliate of HEC, Cougar is offering the 80 Plus Gold rated premium GX series only in the EU at this time. How does the GX-700 fare against other Gold PSUs?

Cougar is a new brand, a wholly-owned German subsidiary of HEC, which is a
long-established Taiwanese computer power supply manufacturer. The GX-700 is
80 Plus Gold approved, a marque for the most efficient computer PSUs in the
marketplace. At time of writing, the Cougar brand is only available in nine
EU countries, not including the UK.

The GX-700 was not available from any of the retail outlets listed on the Cougar
web site; the €160 price cited above is a guess based on the ~€130
and €180~190 prices of the GX-600 and GX-800, respectively. The GX-700
naturally goes up against other premium 80 Plus Gold power supplies such as
the Seasonic X-650 or X-750, the Corsair AX-750 or the Enermax Modu87+ 700.
Our GX-700 sample came directly from Cougar.

PACKAGING & FEATURES

The packaging of the Cougar GX-700 is in keeping with its premium price tag.

Big elaborately decorated box… …with marketing/selling blurbs in four languages. It opens up to show a very well packed product. Detached cables, AC cord, owner manual, velcro straps and screws are the contents.

The multiple 12V lines usually means that there is a current limiter
on each one. However, the claim about "Dynamic Multi-12V" suggests
a single 12V line. The technology is not clearly explained, and which output
connectors carry which 12V lines is not really identified.

VISUAL TOUR

It is an unusually stylish looking power supply, with a couple of rounded edges,
tough-looking pebbled black paint, and a brush-metal gold-colored inset around
the 140mm fan. All the cables, attached and detached, are sleeved. Dimensionally,
it is longer than the norm (front-to-back), at around 7.25", compared to
the more common ~6".

A stylish look and very nice finish. There are eight output sockets along with the attached cables. The vent holes on this side might allow a bit of the heated air in the PSU to enter the case, but with such high efficiency, the amount of heat will be very small. Label boasts all the certifications, including 80 Plus Gold.

OUTPUT CABLES

All the cables are nicely sleeved for a clean tidy look. There are quite a
few permanently attached output cables, which kind of undermines the whole idea
of detachable cables. Many seem too long. The worst is the attached cable for
CPU power which has three different connectors in three breaks on a cable 1.2m
long.

Attached

• 1 – 24P MainBoard (main ATX) – 60cm
• 1 – 8P, 4P+4P and 4P CPU power connectors all on one awkwardly unwieldy
  1.2m cable
• 1 – 6P + 2P PCIE 50cm
• 1 – 6P PCIE 50cm

Modular

• 1 – 2x Molex + 3x SATA 1.1m
• 1 – 2x Molex + 2x SATA 95cm
• 1 – 4x SATA 95cm
• 1 – 2 Molex 65cm
• 1 – Molex to Floppy adapter, 15cm
• 1 – 6-pin PCIe 50cm
• 1 – 8-pin PCIe 50cm

INSIDE

The interior of the Cougar GX-700 is impressively tidy and populated with many
top quality components, as claimed by the marketing blurbs. There is extensive
use of fairly thick insulating plastic which shows a healthy respect for safety
issues.

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.

In our 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.

The 120mm fan responsible for "case airflow" is deliberately
run at a steady low level (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, the noise level of the
exhaust fan is typically not the greatest concern.

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
this 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:

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

The ambient temperature was 20~23°C, and the ambient noise
level was 10~11 dBA. AC input voltage was 118~121V.

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.
It allows reduced cooling airflow, which translates to lower noise. The 80 Plus
Gold standard requires a minimum of 87% efficiency at 20% load, 90% efficiency
at 50% load, and 87% efficiency at full rated maximum load.

One point of note is that the 80 Plus qualifying test is performed
on an open bench top at typical room temperature. In contrast, SPCR’s testing
is conducted at realistic in-PC temperature, often well over 40°C at high
power. This difference results in SPCR test results showing lower efficiency
that the 80 Plus reports at the higher power loads. This is a fundamental flaw
in the 80 Plus test procedure that we’ve observed since the very start of the
80 Plus program; if realistic operational temperature was used for their testing,
very few PSUs rated higher than ~400W would achieve 80 Plus Gold efficiency
at full rated power.

Our sample came very close to the 80 Plus Gold requirements but
didn’t quite meet them all. 87% efficiency was reached at just over 150W, which
is a bit higher than 20% of rated load (140W). 90% efficiency was reached at
a fairly low 250W load, but at 50% of rated power (350W), efficiency was around
89%, not 90% as required. As expected, at full rated 700W load with the hot
test box temperature reaching 50°C, efficiency fell to 3% lower than the
required 87%. The last miss can be forgiven as our test conditons are thermally
far more demading than that required by 80 Plus, but the failure to meet 90%
efficiency at just 350W is a bit surprising. Admittedly, it was a close miss,
falling short by just 1%, and our load power calibration is probably not better
than 1% accurate anyway.

2. DC 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 maintained within ±5%.

Unless a unit goes into overload, it’s rare that we see significant
problems with voltage regulation with the higher quality PSUs SPCR generally
examines. The VR was very good, within ±2% on the 12V line under all
loads. It sagged slightly more at high loads on the lower voltage lines, to
about -3.5% on the 5V line and -2.8% on the 3.3V line. These are fine results.

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. Where voltage regulation is a measure
of variance from spec, ripple is more a measure of tolerance: How much the voltage
is changing at any given time. Ripple is of interest to over- and under-clockers
who push their systems to the limits of what they are actually capable
of rather than relying on what the specs say they should be capable of.

Ripple on the 12V line was low, and rose linearly with load from
a low of under 20mV to just 50mVat full power. The 5V and 3.3V lines also were
well within spec, with ~30mV maximum ripple & noise.

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.

As is the case for most units with active power factor correction
(which, these days, is most reputable brands), PFC was close to perfect, starting
at 0.93 for the minuscule 20W load, and staying at 0.99 through most of the
operating range.

5. LOW LOAD TESTING revealed no problems starting at very
low loads and it stayed operational with no load applied. As advertised, the
power draw in the off (standby mode) was just 0.4W. It also started without
any load, with a 9.8W AC power draw.

6. LOW & 240 VAC PERFORMANCE

The power supply was set to 560W 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 w here the
AC line voltage drops from the 120V norm. Most full-range input 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. Since the Cougar GX-700
is currently sold only in the EU, the high VAC effiiciency is particularly interesting.

Efficiency improved nearly 3% 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. TEMPERATURE & COOLING

The Cougar GX-700 was one of the coolest running PSUs we’ve tested,
with the temperature rise through the unit often staying at just 2°C. This
was due partly to the somewhat aggressive fan controller and the larger than usual 140mm diameter fan, as well as the high average efficiency. Temperature
rise stayed below 4°C until maximum rated power, when it reached 11°C
after about 25 minutes.

7. FAN, FAN CONTROLLER and NOISE

The fan controller tended to favor cooling over lowest noise at
most load levels. The Cougar was pretty quiet to about 200W load, beyond which
the fan speed/noise rose quite linearly with load.

At minimum load , the fan spins at somewhere around 550 RPM, according
to our calibrated strobe, with a measured SPL of just 15 dBA@1m. This is close
to inaudible in most conditions. The noise level rose to 18 dBA@1m at 200W,
which is still pretty darn quiet, though audible. From 200W to 400W, the noise
climbed almost in a straight line from 18 dBA to 32 dBA. That’s subjectively
about a three-fold increase in perceived noise.

The quality of the noise is moot until beyond 200W when it becomes
more obvious. Mostly it is broadband fan noise, quite smooth, centered mostly
in the lower midrange. Overall, it’s a relatively benign noise until >400W
load is reached.

Noise in a Cooler Case

One thing we’ve been examining is how the power supply performs
outside the tough thermal conditions of our standard test. The
recent popularity of cases that isolate the power supply from the rest of the
system make this a relevant question, as the cooler intake air allows the fan
to run slower and quieter. We examine this by running some of the high load
tests with the power supply in free air, away from the tough thermal conditions
of the hot-box.

Outside the hotbox, the fan’s increase in speed occurred at a
higher power level, and its rate of increase was lower. This suggests that in
a case with isolated intake vent for the PSU, the GX-700 would remain inaudible
to over 250W load. This covers a majority of PCs.

COMPARISONS

The comparison table below shows the SPL versus Power Load data on all the
PSUs tested in the anechoic chamber thus far. It’s difficult to rank them, as
the measured SPL varies with power load. The units which are quietest at minimum
load are not always the quietest at midload (100W~300W), which may make them
louder in actual use. Then there’s the noise level at 400W and up, which will
determine the quietest PSUs for high power gaming rigs, during actual gaming.

The GX-700 falls in the bottom third of the pack. At the <200W power loads,
the Cougar quiet enough to be considered extremely quiet. But the noise climbs
too quickly with load. Its overall noise curve is closest to the Coolermaster
M700W and the SilverStone DA700, which were at one point, fairly high up on
this comparison table.

Caution: Please keep in mind that the data in the above table is specific to the conditions of our test setup. Change the cooling configuration, the ambient temperature and any number of other factors, and you could change the point at which the fans start speeding up, as well as the rate of the rise in speed. The baseline SPL is accurate, however, probably to within 1 dBA.

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 and various settings. 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

• Cougar
  GX-700 at various loads in anechoic chamber at one meter
  — idle to >150W (15 dBA@1m)
  — 200W (18 dBA@1m)
  — 250W (20 dBA@1m)
  — 300W (25 dBA@1m)
  — 550W (35 dBA@1m)

Comparatives

• Antec
  TP-750 at various loads in anechoic chamber at one meter
  — idle to >150W (12 dBA@1m)
  — 200W (14 dBA@1m)
  — 300W (18 dBA@1m)
  — 500W (33 dBA@1m)
  — 750W (40 dBA@1m)

• Enermax
  Modu/Pro87+ 500 at various loads in anechoic chamber at one meter
  — idle to >250W (11 dBA@1m)
  — 300W (14 dBA@1m)
  — 400W (20 dBA@1m)
  — 500W (23 dBA@1m)

• Seasonic
  X-650 at various loads in anechoic chamber at one meter
  — idle to >150W (ambient of chamber – 11 dBA@1m)
  — 200W (12 dBA@1m)
  — 250W (14 dBA@1m)
  — 300W (16 dBA@1m)
  — 400W (31 dBA@1m)

• Enermax
  Eco80+ at various loads in anechoic chamber at one meter
  — idle to >90W (11 dBA@1m)
  — 200W (16 dBA@1m)
  — 250W (19 dBA@1m)
  — 300W (26 dBA@1m)
• Seasonic
  M12D 850W at various loads in anechoic chamber at one meter
  — idle to >350W (14 dBA@1m)
  — 400W (24 dBA@1m)
  — 500W (37 dBA@1m)
• Antec
  Signature 650 at various loads in anechoic chamber at one meter
  — idle to 250W (15 dBA@1m)
  — 250~300W (18 dBA@1m)
  — 400W (28 dBA@1m)

CONCLUSIONS

Only a handful of 80 Plus Gold rated PSUs have come through the
SPCR labs thus far. With the likes of the Seasonic X-650 and XX-400, and the
Enermax Modu87+ 500W preceding it, the Cougar GX-700 follows behind some serious
performers.

While its overall performance is excellent and its noise level
quite modest, our sample GX-700 doesn’t quite match the previous Gold performers.
The noise level ramps up at too low in power level to compete with the best,
and its energy efficiency falls a mite shy of 80 Plus Gold requirements. Of
course, if you are in the EU where the Courgar is sold exclusively, the 220~240VAC
power grid will automatically provide a ~3% boost in efficiency, which makes
our quibbles about efficiency a bit moot. The noise performance is bit more
difficult to justify; quieter PSUs have been around for a year or two, mostly
at lower prices.

This is not to say that the GX-700 is not a good PSU; it is an
excellent PSU that will serve just about any desktop computer system well. It
would have been at the top for electrical performance prior to 80 Plus Gold,
and its noise level would also be close to the top a year or two ago. It’s just
that PSU standards are so high these days — the electrical performance,
especially, is actually way better than required for any PC.

As mentioned at the start of the review, this model could not
be found for purchase on line at time of writing. Presumably this is a temporary
stock shortage… but it appears that many 80 Plus Gold models are still missing
in the markets.

Much thanks to Cougar
/ HEC
for the review sample.

* * *

SPCR Articles of Related Interest:
Power Supply Fundamentals

Recommended Power Supplies
SPCR PSU Test Rig V.4
Seasonic X-400 Fanless
Seasonic X-650: Seasonic Hits
Gold
Enermax Modu/Pro87+ 500W
Antec TruePower TP-750

* * *

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this article in the SPCR Forums.