Corsair VX450W: Quiet Value PSU

Power
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7. TEMPERATURE & COOLING

The cooling worked well, especially considering the slow speed of the fan through much of the load range. Temperature rise remained modest and did not reach double digits until about the 200W mark. From 250W to 450W, the temperature rise stayed at about 13~16°C. This suggests a reasonably well-cooled PSU despite the low fan speeds.

8. FAN, FAN CONTROLLER and NOISE

Upon turn on, the PSU fan started at just below 4V, then stabilized at 4.06 within a minute or two. The Sound Pressure Level (SPL) reading was 21 dBA@1m, which was audible at 1m, but quiet and smooth. I listened carefully for any audible buzzing with both samples from a meter away. There was none at this distance above the fan noise at any load. When the fan was stopped with a plastic wire tie jammed into the blades, a bit of buzzing could be heard from about a foot away, but this was about at the same level as fanless PSUs we've tested. In other words, audible buzzing or humming was not an issue with these samples.

The fan noise and voltage remained essentially unchanged in our thermal test rig all the way to about 250W output load. This is extremely quiet performance, close to the very best we've encountered in any PSU.

Beyond 250W, the fan speed and noise climbed quickly, as expected. The overall noise at high loads were actually higher than measured on the HX520/620 samples from last year, despite the fan in the VX450W being rated at lower top speed. A closer look at the measured SPL of many other tested PSUs show lower readings than the VX450W at very high load. In the comparison table below, the >30 dBA@1m readings are highlighted in light green.

Comparison: Various PSUs Noise Vs. Power Output
Model
90W
150W
200W
250W
300W
400W
450W
Corsair VX450W
21
21
21
22
26
44
50
Corsair HX520/620
22
22
22
22
22
29
40
Seasonic S12-430
20
22
25
29
32
37
37
Seasonic S12 Energy Plus 550/650
20
20
20
21
26
38
40
Antec EarthWatts 430
22
22
24
29
37
41
43
Zalman ZM600
25
27
29
30
31
36
40

The above comparison table should not be taken as an absolute. It shows sound pressure levels recorded on SPCR's test platform. The ambient temperature varies a bit, in a range of 20~23°C, and some of the PSUs may have the small advantage of lower ambient temperature during testing. This can help lower the overall noise curve, and more importantly, increase the power level at which the noise starts getting seriously louder. Still, at higher power levels, the temperature in the test box is determined mostly by the load. In any case, in the above test data, several models are about equally quiet up to ~200W load. But only the Corsair HX series has lower measured SPL at 300W. Above 300W, the HX and most other models remain quieter than the VX450W.

For those who do better with graphical representations of data, here's the same information, plotted as curves on a graph. Note that not every PSU was measured at every 50W interval; some data points were interpolated.

With regard to the graph, it should be noted that...

  • In real use, at idle in most PCs in most environments, all the Corsair PSUs, the Seasonics and the Antec Trio 550 would have about the same subjective loudness. All would be perceived as very quiet. It's only with the temperature rise that occurs when the load exceeds 150W that any significant acoustic differences show up among these models.
  • You can see clearly that both the Zalman ZM600 and the Nexus NX8060 have linear fan speed controllers, compared to the other models, all of which have a distinct hinged curve.
  • You can also see how much higher the hinge point has moved, and how much steeper the slope has become in the curves for Seasonic-built PSUs since the S12-430. This is related to improvements in efficiency and cooling, and a continuing focus by Seasonic on PSU acoustics.

Getting back to the Corsair VX450W, the higher SPL readings at higher loads are clearly caused by its plastic fan baffle. It is not a factor when the fan RPM is low, but considerably more turbulence is created when the fan blades are spinning fast in such close proximity. The additional noise at high loads is not meaningful for most silent PC enthusiasts who are unlikely to run systems that draw >200W DC. In such systems, the VX450W will be about as quiet a fan-cooled PSU as you can find on the market. However, for systems that routinely pull over 250W, there's some acoustic benefit to going with the HX series, which is as quiet as the VX450W at lower loads and remains quieter to a higher load.

If you want the best noise performance from the VX450W, use it in a system that draws no more than 300W (DC), and/or ensure that its immediate environmental temperature does not climb much above 30°C. Note that 31°C was the air temperature at the intake side of the VX450W with 300W load. A system with such parameters is not difficult to build today, especially for energy-savvy PC enthusiasts.

MP3 SOUND RECORDINGS

Each of these recording start with 6~10 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 new Corsair VX450W is not aimed at the dual-video card, power-demanding, PC gaming user, but for a much bigger audience: Everyone else. The VX450W delivers clean, stable power that's much more than adequate for the vast majority of PC systems today. Like the HX series, it's among the quietest fan-cooled PSUs we've tested. They are very energy efficient, matching and even surpassing many of 80 Plus certified models we've tested. The sleeved cables are long enough for large cases, and there are enough connectors for very ambitious systems. Corsair's five year warranty remains the longest for any computer power supply we know of.

The best way to take advantage of the VX450W's quiet qualities has already been mentioned: Ensure that the PSU intake air does not exceed 30°C often, nor demand more than ~300W DC output. With a decent case and well selected components, these are easy requirements to meet these days. Following these guidelines will reward you with a PSU that's always very quiet, making the basis for a very quiet computer.

We stated on our review of the Corsair HX520/620 that.... "about the only thing SPCR could ask for are a couple more lower power models for those of us who seek to make a high efficiency, quiet, yet highly capable computer. 300W would be plenty for such a PC in these days of improving CPU efficiency." 450W is considerably higher than what we asked for, but that's OK, as everything else, including price, is certainly right.

Final words: Another great PSU, Corsair.

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SPCR Articles of Related Interest:
Power Supply Fundamentals
Recommended Power Supplies
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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