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 SSR-650TD efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.
In the 600 to 650 W category, there is no opponent able to match the SSR-650TD's amazing efficiency under light and normal loads. Seasonic does an amazing job with this platform. Finally, Super Flower's Titanium-class Leadex units have a worthy opponent.
Efficiency At Low Loads
In the following tests, we measure the SSR-650TD'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 80 W. 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 | 1.188A | 0.492A | 0.480A | 0.196A | 19.60 | 81.60% | 0 RPM | 0 dB(A) | 0.792 |
| 12.250V | 5.014V | 3.329V | 5.008V | 24.02 | 115.2V | ||||
| 2 | 2.406A | 0.990A | 0.989A | 0.395A | 39.70 | 88.76% | 0 RPM | 0 dB(A) | 0.909 |
| 12.249V | 5.012V | 3.326V | 5.003V | 44.73 | 115.2V | ||||
| 3 | 3.624A | 1.488A | 1.500A | 4.999A | 59.82 | 90.47% | 490 RPM | 21.2 dB(A) | 0.953 |
| 12.247V | 5.010V | 3.325V | 4.999V | 66.12 | 115.2V | ||||
| 4 | 4.834A | 1.995A | 1.984A | 0.799A | 79.77 | 92.08% | 490 RPM | 21.2 dB(A) | 0.965 |
| 12.245V | 5.009V | 3.324V | 4.995V | 86.63 | 115.2V |
The PSU operates passively during the first two light-load tests, and our efficiency results are impressive overall. Even with 19.6 W load, efficiency easily surpass the 80 percent mark. Meanwhile, other PSUs struggle to stay above 70 percent.
5VSB Efficiency
The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher efficiency with 100 mA of load, 60 percent or higher with 250 mA of load and 70 percent or higher with 1 A 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 | 0.51 | 73.91% | 0.074 |
| 5.004V | 0.69 | 115.2V | ||
| 2 | 0.251A | 1.25 | 78.13% | 0.159 |
| 4.996V | 1.60 | 115.2V | ||
| 3 | 1.001A | 4.96 | 81.05% | 0.349 |
| 4.960V | 6.12 | 115.2V | ||
| 4 | 3.001A | 14.61 | 79.58% | 0.463 |
| 4.869V | 18.36 | 115.2V |
The 5VSB rail offers decent efficiency, though we expected more from this platform. We are being really picky here, but this is a Titanium-class PSU, so we have to be.
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 | 12.271V | 5.030V | 3.331V | 5.030V | 4.22 | 0.262 |
| 115.1V | ||||||
| Standby | 0.06 | 0.006 | ||||
| 115.1V |
The energy that Seasonic's SSR-650TD consumes at standby is very low, as you can see in the table above.
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 40 °C (104 °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 40 °C (104 °F) to 47 °C (116.6 °F) ambient temperature.
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).
Up to around 250 W load, the PSU operates passively, hence its noise output is zero. Once the fan is engaged, it spins quickly for a short period to exhaust heated air, after which is drops to its lowest speed. The SSR-650TD's overall noise output is really low, making this PSU a great choice if you plan to build a quiet PC.