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 and +12V3 rails, while the +12VB input was connected to the power supply +12V2 and +12V3 rails.
Each +12 V input of our load tester is limited to 33 A, and that is why during test five we had to increase current at the +5 V and +3.3 V inputs more than we usually do.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 6.5 A (78 W) | 13 A (153 W) | 20 A (240 W) | 26.5 A (318 W) | 33 A (396 W) |
| +12VB | 6.5 A (78 W) | 13 A (153 W) | 19.5 A (234 W) | 26.5 A (318 W) | 33 A (396 W) |
| +5 V | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) | 14 A (70 W) |
| +3.3 V | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) | 14 A (46.2 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 | 183.7 W | 356.8 W | 533.4 W | 707.9 W | 901.9 W |
| % Max Load | 20.4% | 39.6% | 59.3% | 78.7% | 100.2% |
| Room Temp. | 46.1° C | 46.4° C | 45.4° C | 46.0° C | 47.8° C |
| PSU Temp. | 49.0° C | 49.6° C | 50.5° C | 50.9° C | 53.2° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 210.3 W | 401.2 W | 609.2 W | 828.0 W | 1102.0 W |
| Efficiency | 87.4% | 88.9% | 87.6% | 85.5% | 81.8% |
| AC Voltage | 114.7 V | 113.2 V | 110.6 V | 108.0 V | 104.4 V |
| Power Factor | 0.975 | 0.988 | 0.996 | 0.999 | 0.998 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The Huntkey X7 900 W can really deliver its labeled wattage at high temperatures.
Efficiency was between 85.58% and 88.9% when we pulled between 20% and 80% of the power supply labeled wattage (i.e., between 180 W and 720 W). When we pulled 900 W from this power supply, however, efficiency dropped to 81.8%, below the 85% minimum promised by the 80 Plus Silver certification. In fact, it even dropped below 80 Plus Bronze level (82 percent). This may have happened for two reasons.
First, there is the temperature. If you follow our reviews, you know that temperature plays a major role in efficiency. The higher the temperature, the lower the efficiency. We test power supplies above 45° C, while the 80 Plus certification process is conducted at 23° C. The second reason we saw efficiency below the expected value is because the AC voltage dropped below 115 V as we increased load.
Voltage regulation was very good, with all voltages closer to their nominal values than required (three percent regulation), except the -12 V output during test one (at -11.43 V) and the +12VB input during test five (+11.52 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.