Efficiency, Temperature, And Noise
Efficiency
Our efficiency testing procedure is detailed here.
Using the results from the previous page, we plotted a chart showing the MasterWatt 1200's efficiency at low loads, and loads from 10 to 110 percent of the PSU's maximum-rated capacity.
Efficiency under normal loads is very high, matching the AX1500i's performance. However, under light loads, the MasterWatt 1200 posts one of the lowest efficiency readings we have ever measured from a high-end PSU. What a shame. Apparently, Enhance tuned this unit with the 10%-100% load region in mind, and with anything lower than 10% of its maximum-rated capacity, efficiency takes a large hit.
Efficiency At Low Loads
In the following tests, we measure the MasterWatt 1200's efficiency at loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dialed were 20, 40, 60 and 80W. This is important for representing when a PC is idle, with power-saving features turned on.
| Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed | Fan Noise | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.203A | 0.481A | 0.475A | 0.194A | 19.57 | 51.87% | 1680 RPM | 39.6 dB(A) | 0.826 |
| 12.077V | 5.119V | 3.350V | 5.105V | 37.73 | 115.1V | ||||
| 2 | 2.438A | 0.976A | 0.984A | 0.390A | 39.71 | 60.62% | 1680 RPM | 39.6 dB(A) | 0.908 |
| 12.083V | 5.102V | 3.348V | 5.079V | 65.51 | 115.1V | ||||
| 3 | 3.672A | 1.466A | 1.492A | 5.061A | 59.82 | 80.17% | 1680 RPM | 39.6 dB(A) | 0.918 |
| 12.086V | 5.093V | 3.346V | 5.061V | 74.62 | 115.1V | ||||
| 4 | 4.897A | 1.964A | 1.970A | 0.790A | 79.72 | 85.81% | 1680 RPM | 39.6 dB(A) | 0.928 |
| 12.081V | 5.084V | 3.344V | 5.044V | 92.90 | 115.1V |
The 20W and 40W efficiency results are an insult for any PSU boasting the 80 PLUS Titanium certification, even at this capacity level. With 60W and above, Cooler Master surpasses the 80% mark.
Cooler Master Connect Screenshots
Below you will find screenshots of the Connect software, which we took during the light-load test sessions.
The software's efficiency readings are nowhere near reality.
5VSB Efficiency
The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher efficiency with 100mA of load, 60 percent or higher with 250mA of load and 70 percent or higher with 1A or more of load.
We take four measurements: one each at 100, 250 and 1000mA, and one with the full load the 5VSB rail can handle.
| Test # | 5VSB | DC/AC (Watts) | Efficiency | PF/AC Volts |
|---|---|---|---|---|
| 1 | 0.101A | 0.50 | 52.08% | 0.046 |
| 4.995V | 0.96 | 115.1V | ||
| 2 | 0.251A | 1.25 | 66.85% | 0.088 |
| 4.985V | 1.87 | 115.1V | ||
| 3 | 1.002A | 4.95 | 77.71% | 0.243 |
| 4.939V | 6.37 | 257.6V | ||
| 4 | 3.502A | 16.76 | 77.74% | 0.417 |
| 4.787V | 21.56 | 115.1V |
We measure very low 5VSB efficiency. Enhance should do a better job here.
Power Consumption In Idle And Standby
In the table below, you'll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (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).
| Mode | 12V | 5V | 3.3V | 5VSB | Watts | PF/AC Volts |
|---|---|---|---|---|---|---|
| Idle | 12.095V | 5.156V | 3.358V | 5.155V | 9.02 | 0.388 |
| 115.1V | ||||||
| Standby | 0.33 | 0.016 | ||||
| 115.1V | ||||||
Phantom power is higher than usual in this discipline. Still, it is lower than 0.5W.
Fan RPM, Delta Temperature And Output Noise
Our mixed noise testing is described in detail here.
The first chart below illustrates the cooling fan's speed (in RPM), and the delta between input and output temperature. The results were obtained at 38 °C (100.4 °F) to 47 °C (116.6 °F) ambient temperature.
The next chart shows the cooling fan's speed (again, in RPM) and output noise. We measured acoustics from one meter away, inside a small, custom-made anechoic chamber with internals completely covered in sound-proofing material (be quiet! Noise Absorber kit). Background noise inside the chamber was below 18 dB(A) during testing, and the results were obtained with the PSU operating at 38 °C (100.4 °F) to 47 °C (116.6 °F) ambient temperature.
The following graphs illustrate the fan's output noise and speed over the PSU's operating range. The same conditions of the above graph apply to our measurements, though the ambient temperature was between at 28 °C (82.4 °F) to 30 °C (86 °F).
Under normal operating temperatures and with the default mode selected, the PSU is quiet given its high capacity. Passive operation wasn't active during our cross-load tests because temperatures inside the PSU need to be lower than 20 °C. If you select Silent mode, the PSU operates passively during light loads, resulting in lower output noise.
The graph above looks like a messy canvas due to the small fan speed variations that our equipment recorded.