Athena Power AP-MFATX40P8 400 W 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 li
sted 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, while the +12VB input was connected to the power supply +12V2 rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 2.5 A (30 W) | 5.5 A (66 W) | 8 A (96 W) | 10.5 A (126 W) | 14 A (168 W) |
| +12VB | 2.5 A (30 W) | 5.5 A (66 W) | 8 A (96 W) | 10.5 A (126 W) | 13 A (156 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) | 1.5 A (7.5 W) | 2 A (10 W) | 2.5 A (12.5 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 | 77.8 W | 153.1 W | 235.2 W | 312.8 W | 398.6 W |
| % Max Load | 19.5% | 38.3% | 58.8% | 78.2% | 99.7% |
| Room Temp. | 44.8° C | 44.6° C | 45.2° C | 45.8° C | 46.3° C |
| PSU Temp. | 45.9° C | 44.9° C | 45.3° C | 47.6° C | 52.8° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 94.6 W | 178.8 W | 275.5 W | 373.1 W | 487.3 W |
| Efficiency | 82.2% | 85.6% | 85.4% | 83.8% | 81.8% |
| AC Voltage | 116.5 V | 115.9 V | 114.9 V | 113.9 V | 112.6 V |
| Power Factor | 0.942 | 0.969 | 0.985 | 0.99 | 0.993 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The Athena Power AP-MFATX40P8 passed our tests, which really surprised us, since the 350 W model failed them. We are very happy to see that the revision Athena Power did to this unit really fixed the efficiency and noise level issues.
Efficiency was between 81.8% and 85.6% during our tests, virtually matching the values promised by the 80 Plus Bronze certification. Efficiency with the power supply delivering 400 W was a tiny bit below the 82% promised by the 80 Plus Bronze certification, but 81.8% was a good result anyway. As we always explain, the tests done during the 80 Plus certification process are conducted at 23° C, and efficiency drops as we increase temperature. (We test power supplies between 45° C and 50° C.)
Voltage regulation was very good, with all voltages closer to their nominal values than required (three percent regulation), except for the +5 V output at tests one and two (+5.21 V and +5.19 V, respectively) and the -12 V output at test one (-11.41 V). These outputs were still inside the allowed 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.