Enermax Tomahawk 500 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 how the reviewed unit behaved 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 power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (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. On 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.
Note: We are now using the names +12VA and +12VB for the two inputs from our load tester because some people were thinking that the “+12V1” and “+12V2” names present on our table referred to the power supply rails, which is not the case.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 4 A (48 W) | 7 A (84 W) | 11 A (132 W) | 14.5 A (174 W) | 17.5 A (210 W) |
| +12VB | 3 A (36 W) | 7 A (84 W) | 10 A (120 W) | 14 A (168 W) | 17 A (204 W) |
| +5V | 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) | 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 | 103.4 W | 194.0 W | 305.6 W | 397.9 W | 484.1 W |
| % Max Load | 20.7% | 38.8% | 61.1% | 79.6% | 96.8% |
| Room Temp. | 43.1° C | 42.6° C | 44.6° C | 47.4° C | 42.6° C |
| PSU Temp. | 48.1° C | 47.8° C | 48.8° C | 51.0° C | 51.9° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 122.7 W | 229.5 W | 371.7 W | 501.2 W | 630.0 W |
| Efficiency | 84.3% | 84.5% | 82.2% | 79.4% | 76.8% |
| AC Voltage | 112.6 V | 111.8 V | 110.4 V | 108.4 V | 107.9 V |
| Power Factor | 0.976 | 0.991 | 0.995 | 0.997 | 0.998 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
Enermax Tomahawk 500 W can really deliver its labeled wattage at high temperatures.
Efficiency was high when we pulled between 20% and 40% from its labeled load (between 100 W and 200 W), above 84%. When we pulled 60% from its labeled load (around 300 W), efficiency was still decent at 82.2%. But pulling more than that efficiency dropped below the 80% mark.
Voltages were always inside the allowed range and noise and ripple were always below ultra low. Below you can see these levels with the power supply delivering 484.1 W (test five). The maximum allowed is 120 mV for the +12 V output and 50 mV for the +5 V and +3.3 V outputs. All numbers are peak-to-peak figures.
Figure 17: +12VA input from load tester at 484.1 W (25.2 mV).
Figure 18: +12VB input from load tester at 484.1 W (24.2 mV).
Figure 19: +5V rail with power supply delivering 484.1 W (11 mV).
Figure 20: +3.3 V rail with power supply delivering 484.1 W (14.6 mV).
Let’s see if we can pull more than 500 W from this unit.