Cooler Master eXtreme Power Plus 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 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 +12V2 rail, while +12VB was connected to the power supply +12V1 rail (EPS12V connector).
| 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) |
| +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 (5 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 A (10 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 | 78.2 W | 156.4 W | 233.3 W | 309.6 W | 392.4 W |
| % Max Load | 19.6% | 39.1% | 58.3% | 77.4% | 98.1% |
| Room Temp. | 44.7° C | 43.9° C | 44.0° C | 45.5° C | 47.7° C |
| PSU Temp. | 48.0° C | 47.7° C | 47.5° C | 48.0° C | 49.6° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Fail on +12 V | Fail on +12 V |
| AC Power | 106.5 W | 199.2 W | 299.2 W | 405.4 W | 534.0 W |
| Efficiency | 73.4% | 78.5% | 78.0% | 76.4% | 73.5% |
| AC Voltage | 116.5 V | 115.8 V | 114.7 V | 113.5 V | 111.9 V |
| Power Factor | 0.597 | 0.639 | 0.648 | 0.658 | 0.670 |
| Final Result | Pass | Pass | Pass | Fail | Fail |
Cooler Master eXtreme Power Plus 400 W can really deliver its labeled power at high temperatures. However, power isn’t everything.
Efficiency was always below 80%, varying between 73% and 78%.
Voltages were inside the required range. In fact during the first three tests all voltages were inside a 3% range from their nominal values. Translation: voltages closer to their nominal voltages than required, since ATX12V specification allows a 5% tolerance. During tests four and five +12 V outputs got outside this tight regulation, but they were still inside their required values.
But what really kills this unit is its very high noise and ripple levels. During tests four and five these levels surpassed the 120 mV limit on +12 V outputs, at 128.8 mV and 147.6 mV, respectively. Below you can see the results for test five. The maximum allowed is 120 mV on +12 V and 50 mV on +5 V and +3.3 V. All these numbers are peak-to-peak figures.
Figure 16: +12VA input from load tester at 392.4 W (147.6 mV).
Figure 17: +12VB input from load tester at 392.4 W (144.6 mV).
Figure 18: +5 V rail with power supply delivering 392.4 W (34.4 mV).
Figure 19: +3.3 V rail with power supply delivering 392.4 W (19.2 mV).
Since this unit was already presenting noise levels above the maximum allowed, we decided not to overload it.