EfficiencyUsing the efficiency results from the previous page, we plotted a chart showing the V550S's efficiency at both low loads and loads equal to 20%-110% of the PSU's maximum-rated load.
As you can see, the V550S is hands down the best unit we have tested so far, beating PSUs with higher official efficiency certifications. Its performance is impressive, beating the next unit below it by a huge margin. Also, with normal loads, the PSU performed very well by taking third place on our charts and being very close to the top two Platinum units.
Efficiency at Low LoadsThe next tests measure the efficiency of the V550S at loads much lower than 20% of its maximum-rated load (the lowest load the 80 Plus Standard measures). The loads we dialed were 40 W, 60 W, 80 W, and 100 W (for PSUs with over 500 W of capacity). This is important for settings where the PC is in idle mode with Power Saving turned on.
| Efficiency at Low Loads |
Cooler Master V550S
|Test #||12 V||5 V||3.3 V||5 VSB||Power|
|Efficiency||Fan Speed||Fan Noise||PF/AC |
|1||1.796A||1.994A||1.983A||0.195A||39.65W||87.70%||630 RPM||32.7 dBA||0.609|
|2||3.349A||1.994A||1.984A||0.395A||59.73W||90.72%||630 RPM||32.7 dBA||0.729|
|3||4.893A||1.993A||1.983A||0.600A||79.70W||92.04%||630 RPM||32.7 dBA||0.803|
|4||6.441A||1.993A||1.984A||0.800A||99.69W||92.37%||630 RPM||32.7 dBA||0.849|
This is the perfect PSU for a system with very low energy demands. We have never before seen a PSU register close to 88% efficiency with a 40 W load. It also scored well over 90% in the other three low load tests! Enhance did an awesome job and their "3D design" probably isn't a mere marketing gimmick—it also contributes to these mind-blowing test results.
5VSB EfficiencyThe ATX spec states that the 5VSB standby supply's efficiency should be as high as possible and recommends 50% or higher efficiency with 100 mA of load, 60% or higher with 250 mA of load, and 70% or higher with 1 A or more of load.
We will take four measurements: one at 100, 250, and 1000 mA each, and one with the full load the 5VSB rail can handle.
| 5VSB Efficiency|
Cooler Master V550S
|Test #||5VSB||Power (DC/AC)||Efficiency||PF/AC Volts|
Efficiency on the 5VSB rail is pretty good at all load levels, even surpassing 80% with full load.
Power Consumption in Idle & StandbyIn the table below, you will find the power consumption and the voltage values of all rails (except -12V) when the PSU is in idle mode (powered on but without any load on its rails) and the power consumption when the PSU is in standby mode (without any load at 5VSB).
| Idle / Standby |
Cooler Master V550S
|Mode||12 V||5 V||3.3 V||5VSB||Power (AC)||PF/AC Volts|
At around one third of the limit, phantom power is dead low. The V550S definitely meets ErP Lot 6 2013 requirements.
Fan RPM, Delta Temperature & Output NoiseThe cooling fan's speed (RPMs) and the delta difference between input and output temperature are illustrated in the following chart. The following results were obtained at 38°C-45°C ambient.
A chart that shows the cooling fan's speed (RPMs) and the output noise follows. We measure the fan's noise from 1 meter away, inside a small custom-made anechoic chamber whose internals are completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit). The background noise inside the anechoic chamber was below 30 dBA during testing, and the results were obtained with the PSU operating at 38°C-45°C ambient.
The following graph illustrates the fan's output noise throughout the PSU's entire operating range. The same conditions of the above graph apply to our measurements, but the ambient in this case was between 28 and 30°C.
The fan may be noisy at full speed, but the control circuit keeps its speed at a minimum throughout most of the unit's operational range, allowing for a really quiet operation, and nor does the fan spin up significantly at high load since there is no need to, as this PSU runs a very cold operation by keeping energy dissipation to a minimum, making it one of the quietest PSUs we have tested to date, at least under normal conditions.