ADATA BN-550 Power Supply Review
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 input was connected to the power supply +12V1 rail, and the +12VB input was connected to the power supply +12V1 and +12V2 rails (EPS12V connector).
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 4 A (48 W) | 8 A (96 W) | 12 A (144 W) | 16.5 A (198 W) | 20.5 A (246 W) |
| +12VB | 4 A (48 W) | 8 A (96 W) | 12 A (144 W) | 16 A (192 W) | 20.5 A (246 W) |
| +5V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 5 A (25 W) | 6 A (30 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 5 A (16.5 W) | 6 A (19.8 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 2.5 A (12.5 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 | 114.8 W | 218.5 W | 332.6 W | 442.2 W | 550.8 W |
| % Max Load | 20.9% | 39.7% | 60.5% | 80.4% | 100.1% |
| Room Temp. | 45.2° C | 44.8° C | 44.4° C | 45.1° C | 48.0° C |
| PSU Temp. | 46.7° C | 44.6° C | 44.9° C | 46.1° C | 49.5° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 135.5 W | 253.7 W | 390.2 W | 528.2 W | 674.0 W |
| Efficiency | 84.7% | 86.1% | 85.2% | 83.7% | 81.7% |
| AC Voltage | 116.3 V | 115.1 V | 113.2 V | 111.6 V | 110.1 V |
| Power Factor | 0.987 | 0.958 | 0.973 | 0.983 | 0.989 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The ADATA BN-550 can really deliver its labeled wattage.
Efficiency was high when we pulled between 20% and 80% of the labeled wattage (i.e., between 110 W and 440 W), ranging from 83.7% and 86.1%. At 550 W, efficiency dropped to 81.7%, which is close enough to the 82% minimum required for the 80 Plus Bronze certification.
Voltage regulation was very good, with all positive voltages within 3% of their nominal values, except for the +5 V output during tests three, four, and five (but it was still inside the proper range; the -12 V output was outside this tighter regulation during tests one and two but was still inside the proper range as well). This means that voltages were closer to their nominal values than required by the ATX12V specification, which says positive voltages must be within 5% of their nominal values and negative voltages must be within 10% of their nominal values.
Noise and ripple levels were always below the maximum allowed, but a little too high at the +12 V outputs for us to consider this unit as “flawless.” Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures.
Figure 17: +12VA input from load tester during test five at 550.8 W (83.4 mV)
Figure 18: +12VB input from load tester during test five at 550.8 W (84.5 mV)
Figure 19: +5V rail during test five at 550.8 W (23.4 mV)
Figure 20: +3.3 V rail during test five at 550.8 W (24.6 mV)
Let’s see if we can pull more than 550 W from this unit.