Corsair CX400W Power Supply

Power
Viewing page 6 of 7 pages. Previous 1 2 3 4 5 6 7 Next

8. FAN, FAN CONTROLLER and NOISE

The fan voltage was monitored via a small wire soldered onto the positive terminal of the Adda fan. With no load, all the way up to about 90W, the fan remained at a quiet 4.18V, audible from 1m but generally a low, unoffensive hum, registering 22dBA@1m. Commutator chatter could only be heard with a discerning ear at less than a foot away, and did not seem to increase at higher speeds. At 150W and above, however, the fan sped up to maintain reasonable cooling, increasing to a lightly audible 26dBA@1m at 150W. The noise increased to a plainly audible, turbulent 32dBA@1m after running for some time at 200W. At 250W, the fan hit its maximum voltage of 11.2V, generating a very noticable hum at 35dBA@1m, all the way up to and throughout maximum load.

The screen captures below from our SpectraPLUS audio spectrum analyzer should be self-explanatory. Note that the noise floor of the anechoic chamber is just under 11 dBA. The red line is the ambient level of the chamber without any noise sources.


At around 150W, the fan noise became plainly audible, with higher frequency components becoming audible and apparent, and the sound gaining more broadband noise.

In a modern high performance case with independent cooling airflow for the power supply, thermal condition are much milder than in a conventional case or in our test box. The PSU does not have to work nearly as hard to exhaust hot air from the downstream components. As in our most recent PSU reviews, we performed a noise/load test out of the hot box to simulate noise performance in a modern, high performance case.

Corsair CX400W SPL: In Hot Box vs. Out
Power load
90W
150W
200W
250W
300W
in hot box
19
26
32
35
35
out
19
19
24
30
35
Measurements are in dBA@1m

On the test bench with ambient room temperature at 23¬įC, the fan in the CX400W stayed quietly below 30dBA@1m until 250W. The overall noise-to-power curve is still considerably steeper than most of the top rated PSUs to emerge from SPCR testing, but it's considerably better than inside the hot box, as expected. With some care in thermal design and keeping maximum component power demand to no higher than ~200W, a DIY system builder should be able to assemble a very quiet PC with the Corsair CX400W.

COMPARISONS

The comparison table below shows the SPL versus Power Load data on all the PSUs tested in the anechoic chamber thus far.

Comparison: Various PSUs Noise Vs. Power Output in Anechoic Chamber
Model
90W
150W
200W
250W
300W
400W
500W
6-700W
850W
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
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
Coolermaster M700W
14
14
18
21
25
27
34
34
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
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
Corsair CX400W
19
26
32
35
35
35
35
n/a
n/a
The green boxes represent >30 dBA@1m SPL.
*Guesstimates based on the Modu82+ 425's idle in the chamber and the Modu82+ 625's load test.

The Corsair CX400W is obviously one of the noisier power supplies we've tested in the past year. It stopped performing "quietly" (<30dBA@1m SPL) at a rather low 200W load. It may not be quiet enough for silent PC enthusiasts, but it will likely be quiet enough for many mainstream users, especially in systems without power hungry video cards..

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.



Previous 1 2 3 4 5 6 7 Next

Power - Article Index
Help support this site, buy the Corsair 400 Watt Power Supply from one of our affiliate retailers!