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

Power
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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.

Cougar GX-700 SPL: In Hot Box vs. Out
Power load
90W
150W
200W
250W
300W
400W
550W
700W
in hot box
15
15
18
20
25
32
35
36
out
15
15
15
17
21
25
35
35
Measurements are in dBA@1m

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.

PSU Noise (dBA@1m) vs. Power in Hotbox/Anechoic Chamber
Model
90W
150W
200W
250W
300W
400W
500W
6-700W
850W
Seasonic X-400 Fanless
il*
il
il
il
il
il
n/a
n/a
n/a
Enermax Modu/Pro87+ 500
11
11
11
11
14
20
23
n/a
n/a
Seasonic X-650
<10
11
12
14
16
31
31
32
n/a
Nexus Value 430
11
11
16
18
18
19
n/a
n/a
n/a
Nexus NX-5000
11
11
12
14
22
24
25
n/a
n/a
Antec CP-850
12
12
12
14
14
26
40
44
45
Enermax Eco80+ 500W
<11
12
16
19
26
32
33
n/a
n/a
Seasonic M12D 850W
14
14
14
14
14
24
37
42
42
Enermax Modu82+ 625*
13
13
14
15
16
26
36
37
n/a
Antec TP-750
12
12
14
14
18
33
40
40
n/a
Chill Innovation CP-700M
15
15
15
15
17
30
34
34
n/a
Antec Signature 650
15
15
15
18
18
28
36
47
n/a
Coolermaster M700W
14
14
18
21
25
27
34
34
n/a
Cougar GX-700
15
15
18
20
25
32
35
36
n/a
SilverStone DA700
18
18
18
18
23
32
35
41
n/a
Nexus RX-8500
14
14
17
22
28
32
32
33
33
NesteQ ECS7001
22
22
22
21
23
25
36
37
n/a
PCPC Silencer 610
20
24
24
24
24
30
40
50
n/a

The green boxes are >30 dBA@1m SPL.
*il = immeasurably low in any environment

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.



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