Load Tests
Contents
We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.”
First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.
If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.
The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 4 A (48 W) | 9 A (108 W) | 13 A (156 W) | 17.5 A (210 W) | 21.5 A (258 W) |
| +12VB | 4 A (48 W) | 9 A (108 W) | 13 A (156 W) | 17.5 A (210 W) | 21.5 A (258 W) |
| +5 V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 W) |
2 A (10 W) | 3 A (15 W) |
| -12 V | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) |
| Total | 114.7 W | 241.8 W | 354.4 W | 478.4 W | 597.4 W |
| % Max Load | 19.1% | 40.3% | 59.1% | 79.7% | 99.6% |
| Room Temp. | 46.4° C | 45.0° C | 45.6° C | 47.0° C | 44.9° C |
| PSU Temp. | 48.2° C | 47.7° C | 47.8° C | 48.7° C | 50.2° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 134.5 W | 280.2 W | 416.7 W | 574.1 W | 734.0 W |
| Efficiency | 85.3% | 86.3% | 85.0% | 83.3% | 81.4% |
| AC Voltage | 117.1 V | 115.7 V | 114.4 V | 112.9 V | 111.2 V |
| Power Factor |
0.995 |
0.996 |
0.997 |
0.997 |
0.996 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The PC Power & Cooling Silencer Mk III 600 W can really deliver its labeled wattage at high temperatures.
Efficiency was between 83.3% and 86.3% when we pulled between 20% and 80% of the unit’s labeled wattage (i.e., between 120 W and 480 W), but at full load, efficiency dropped a little bit below the 82% mark promised by the 80 Plus Bronze certification, at 81.4 percent. This happens because the 80 Plus tests are conducted at 23° C. We test power supplies at a temperature of at least 45° C, and efficiency drops with temperature.
Voltage regulation was excellent, with all positive voltages closer to their nominal values than necessary (three percent regulation). The -12 V output was outside this tighter range during test one, but still inside the allowed margin. All voltages were still inside the proper range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.
Let’s discuss the ripple and noise levels on the next page.
