Kingwin Lazer Platinum 550W Power Supply

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7. TEMPERATURE, COOLING & NOISE

A notice on a loose piece of paper in the LZP-550 package cautions that the fan does not spin when the unit is first turned on. On the product web page, a link to ECO Intelligent Thermal Control System (Patent) takes you to the following illustration:

In essence it is a "semi-passive" fan that comes on only when high temperature is reached. The illustration above states that the trigger temperature is 65~70°C, and the fan will stop spinning again once the temperature drops to 45~50°C. (This implies, by the way, that the rated power is valid to 45~50°C.) It is not clear just where in the PSU this temperature is monitored.

What is very clear is that at all but the maximum loads, the fan hardly ever comes on. This is why N/A is indicated for SPL: The noise emitted by the Kingwin LZP-550 during testing was below the 10 dBA noise floor of the anechoic chamber. The fan came on only at full power, and not continuously. It came on initially for about two minutes, then turned off for about five minutes before turning back on again. The relatively cool ambient air quickly cooled the interior of the PSU to 45~50°C. The measured noise when the fan did come on was just 16 dBA@1m, quiet enough to go unnoticed in many environments.

The LZP-550 was not completely noise-free when the fan was not running. At very low loads, with certain combinations of the 5Vsb current, a high pitched noise could be heard clearly from very close distance (under 2-3 feet). As load was increased, this electronic noise faded, but then returned with increased complexity, with several different pitch tones audible at various loads. This noise did not exceed the noise floor of the anechoic chamber, however, and was thus not possible to measure easily. It might be audible to individuals with very sensitive hearing working in an environment with little or no other noise, with this PSU powering a fanless PC in close proximity — say a meter. For 98% of users who employ fans in their PCs, the LZP-550 will rarely be heard.

One complication that arose during testing was the difficulty of measuring temperature. Since the unit was operating in free air, the ambient intake temperature was 21~22°C, but even though the internal temperature had to be rising with increased load, the absence of forced air blowing the heat out toward our sensor mounted at the exhaust grill meant the "exhaust" temperature rose very little. It is probably not a good indication of... anything, in this review.

IN THE HOT BOX

Even when exposed to the heat of the hotbox, the LZP-550 fan did not turn on except at high test loads. The 16 dBA@1m cited for the 400W load is only true part of the time: It stayed off for some 10 minutes at this load before the fan turned on, and it stayed on for only about two minutes. The total time at this load was around 20 minutes, and the fan did not come on again. But after extended operation in the hotbox at 500W load and higher, with the exhaust temperature reaching as high as 69°C, the fan came on and sped up to a higher speed (likely the 1300 RPM maximum it is rated for), where the noise level measured 22 dBA@1m. It stayed at this speed for a good 7~8 minutes before slowing and quieting to 16 dBA@1m, but it did not stop spinning as long as the load was 500W or higher in the hotbox. The overall quality of fan noise even at 22 dBA@1m was smooth and benign, without tonal peaks.

Kingwin LZP-550 SPL: In Hot Box vs. Out
Power load
90W
150W
200W
250W
300W
400W
500W
550W
out
N/A
N/A
N/A
N/A
N/A
N/A
N/A
16*
in hot box
N/A
N/A
N/A
N/A
N/A
16*
22
22
Measurements are in dBA@1m
* See note in text above.

COMPARISONS

The comparison table below shows the SPL versus Power Load data on all the PSUs tested in the hotbox. 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 Kingwin Lazer Platinum LZP-550 acoustics in the hotbox is at the top of the pack, aside from the completely fanless Seasonic X-400 (and X-460). At every load up to its maximum, the unit is quieter than all other tested PSUs.

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
<10*
<10
<10
<10
<10
<10
n/a
n/a
n/a
Kingwin Lazer Platinum LZP-550
<10*
<10
<10
<10
<10
16
22
n/a
n/a
Enermax Modu/Pro87+ 500
11
11
11
11
14
20
23
n/a
n/a
Corsair AX850
<10
<10
12
15
18
25
35
38
39
Seasonic X-650
<10
<10
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
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.
*<10= below the ambient of our anechoic chamber; immeasurably low @1m in any environment

The new comparison table below shows the SPL versus Power Load data on PSUs tested in ambient room temperature, typically 20~24°C. It is most relevant when PSUs are used in cases that provide wide open access to cooler outside air for the PSU cooling fan.

PSU Noise (dBA@1m) vs. Power in Ambient Room Temperature
Model
90W
150W
200W
250W
300W
400W
500W
6-700W
850W
Kingwin Lazer Platinum LZP-550
<10*
<10
<10
<10
<10
<10
16
n/a
n/a
Seasonic X-400 Fanless
<10*
<10
<10
<10
<10
<10
n/a
n/a
n/a
Enermax Modu/Pro87+ 500
11
11
11
11
11
11
18
n/a
n/a
Corsair AX850
<10
<10
<10
11~13
12
13
17
24
35
Seasonic X-650
<10
<10
<10
<10
<10
16
27
32
n/a
Nexus NX-5000
11
11
12
12
12.5
14
19
n/a
n/a
Antec CP-850
12
12
12
12
12
14
20
24
40
Enermax Eco80+ 500W
<11
12
12
16
20
23
28
n/a
n/a
Antec TP-750
12
12
12
14
15
27
31
40
n/a
Cougar GX-700
15
15
15
17
21
25
35
35
n/a

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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