Antec High Current Pro 750 W Power Supply Review
Ripple and Noise 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 rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 5.5 A (66 W) | 11 A (132 W) | 16.5 A (198 W) | 21.5 A (258 W) | 27.5 A (330 W) |
| +12VB | 5.5 A (66 W) | 11 A (132 W) | 16 A (192 W) | 21.5 A (258 W) | 27.5 A (330 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 | 141.1 W | 297.4 W | 441.0 W | 584.4 W | 746.4 W |
| % Max Load | 18.8% | 39.7% | 58.8% | 77.9% | 99.5% |
| Room Temp. | 47.0° C | 46.7° C | 47.2° C | 44.2° C | 45.8° C |
| PSU Temp. | 52.3° C | 52.2° C | 52.7° C | 52.8° C | 55.0° C |
| Voltage Regulation | Pass | Pass | Pass | See Text | See Text |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 164.9 W | 333.8 W | 496.3 W | 662.0 W | 855.0 W |
| Efficiency | 85.6% | 89.1% | 88.9% | 88.3% | 87.3% |
| AC Voltage | 114.9 V | 112.7 V | 111.0 V | 109.4 V | 107.2 V |
| Power Factor | 0.988 | 0.99 | 0.996 | 0.998 | 0.998 |
| Final Result | Pass | Pass | Pass | Fail | Fail |
The 80 Plus Gold certification guarantees minimum efficiencies of 87% at 20% load, 90% at 50% load, and 87% at 100% load. However, in our tests, the Antec High Current Pro 750 W presented 86.5% efficiency at 20% load. We didn’t test this power supply at 50% load, but considering that we saw 89.1% efficiency at 40% load and 88.9% efficiency at 60% load, it may be possible that this unit is able to achieve 90% efficiency at 50% load. At full load, we saw 87.3% efficiency. Always keep in mind that we test power supplies between 45° C and 50° C, while the 80 Plus tests are conducted at 23° C, and efficiency drops as temperature increases.
The main problem with this power supply during our tests, however, was voltage regulation. With the first sample we received, the +3.3 V output dropped to +3.07 V when we pulled 750 W from this unit. On the other hand, all other outputs were within 3% of their nominal value during all tests, except the +3.3 V output during test four (at +3.18 V) and +5VSB at test five (at +4.85 V).
Considering that we might have received a defective sample, we requested a second sample from Antec. The +3.3 V output of the second sample was always within 3% of its nominal value; however, now the +5VSB output was the one that dropped below the minimum allowed, at +4.65 V during test four and at +4.59 V during test five. This output was within 3% of its nominal value during test one; but at test two, it dropped to +4.84 V; and at test three, it dropped to +4.77 V. All other outputs were within 3% of their nominal values.
Since we test power supplies at high temperatures, we wondered if this problem was not being caused by high temperature. We let the power supply cool down and retested the samples at 25° C, with the same results.
Antec sent us a third sample of this power supply, which finally passed our voltage regulation tests. With this sample, all voltages were closer to their nominal values than required (3% regulation), except the +5VSB output during test five, which was at +4.81 V, 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.