Efficiency, Temperature, And Noise
Efficiency
Our efficiency testing procedure is detailed here.
Using results from the previous page, we plotted a chart showing the Tokamak 1500's efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.
Efficiency-wise, this platform performs well, taking over the top spot under normal loads and scoring second place under light ones.
Efficiency At Low Loads
In the following tests, we measure the Tokamak 1500's efficiency under 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 | 1.205A | 0.489A | 0.475A | 0.195A | 19.68 | 66.40% | 850 RPM | 33.1 dB(A) | 0.743 |
| 12.136V | 5.052V | 3.368V | 5.045V | 29.64 | 115.0V | ||||
| 2 | 2.432A | 0.980A | 0.979A | 0.397A | 39.76 | 77.04% | 850 RPM | 33.1 dB(A) | 0.844 |
| 12.133V | 5.052V | 3.368V | 5.040V | 51.61 | 115.0V | ||||
| 3 | 3.662A | 1.475A | 1.483A | 5.036A | 59.87 | 82.72% | 850 RPM | 33.1 dB(A) | 0.886 |
| 12.131V | 5.052V | 3.368V | 5.036V | 72.38 | 115.0V | ||||
| 4 | 4.883A | 1.977A | 1.958A | 0.795A | 79.80 | 85.29% | 850 RPM | 33.1 dB(A) | 0.907 |
| 12.129V | 5.050V | 3.368V | 5.030V | 93.56 | 115.0V |
We would like to see a >70% reading with 20W load, but we're getting picky there since this is a 1.5kW unit and 20W is only 1.3% of its rated capacity. The main problem we have is with fan noise, which could be a lot less intrusive if Rosewill used a lower minimum or implemented a semi-passive mode.
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.Â
| Test # | 5VSB | DC/AC (Watts) | Efficiency | PF/AC Volts |
|---|---|---|---|---|
| 1 | 0.102A | 0.50 | 70.42% | 0.030 |
| 4.948V | 0.71 | 115.1V | ||
| 2 | 0.252A | 1.25 | 77.16% | 0.068 |
| 4.942V | 1.62 | 115.1V | ||
| 3 | 1.002A | 4.93 | 83.28% | 0.217 |
| 4.925V | 5.92 | 115.1V | ||
| 4 | 3.002A | 14.62 | 82.14% | 0.415 |
| 4.869V | 17.80 | 115.1V |
The 5VSB rail is highly efficient, as you can see in the table and graphs above. Only Thermaltake's TPG-1250D-T achieves an overall higher 5VSB efficiency score.
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 | 12.135V | 5.054V | 3.369V | 5.053V | 8.62 | 0.335 |
| 115.1V | ||||||
| Standby | 0.07 | 0.003 | ||||
| 115.1V | ||||||
Standby power consumption is very low, giving Rosewill a big advantage.
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 34°C (93.2°F) to 45°C (113°F) ambient temperature.  Â
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 34°C (93.2°F) to 45°C (113°F) ambient temperature.Â
The following graph illustrates the fan's output noise 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). Â
This is a noisy PSU, no doubt about that. With more than 1.1kW of load you're going to want earplugs. Given our high efficiency measurements, Rosewill could stifle some of the noise by using a more relaxed fan profile. Fortunately, up to around 900W in normal ambient conditions, the fan's noise is low enough in the 31-34 dB(A) region.