Cooler Master eXtreme Power Plus 550 W Power Supply Review
Load Tests
Contents
We conducted several tests with this power supply, as descri
bed in the article Hardware Secrets Power Supply Test Methodology.
This time we made more detailed tests, starting from 85 W and increasing load little by little until we could see the maximum amount of power we could extract from the reviewed unit.
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 +12VB was connected to the power supply “+12V2” rail (EPS12V connector).
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 3 A (36 W) | 3.5 A (42 W) | 4.5 A (54 W) | 5.5 A (66 W) | 6.25 A (75 W) |
| +12VB | 2.5 A (30 W) | 3.25 A (39 W) | 4 A (48 W) | 5 A (60 W) | 6 A (72 W) |
| +5V | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 A) | 1.5 A (7.5 A) | 2 A (10 W) |
| +3.3 V | 1 A (5 W) | 1 A (5 W) | 1.5 A (4.95 W) | 1.5 A (4.95 W) | 2 A (6.6 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (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 | 84.6 W | 99.2 W | 124.4 W | 147.8 W | 172.7 W |
| % Max Load | 15.4% | 18.0% | 22.6% | 26.9% | 31.4% |
| Room Temp. | 41.6° C | 41.2° C | 41.1° C | 41.5° C | 41.9° C |
| PSU Temp. | 44.9° C | 44.9° C | 44.9° C | 44.9° C | 45.1° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 123.3 W | 139.8 W | 169.8 W | 197.1 W | 227.5 W |
| Efficiency | 68.6% | 71.0% | 73.3% | 75.0% | 75.9% |
| AC Voltage | 116.2 V | 116.0 V | 115.7 V | 115.4 V | 115.2 V |
| Power Factor | 0.638 | 0.643 | 0.655 | 0.664 | 0.673 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
| Input | Test 6 | Test 7 | Test 8 | Test 9 | Test 10 |
| +12VA | 7.5 A (90 W) | 8.25 A (99 W) | 9.25 A (111 W) | 10 A (120 W) | 11 A (132 W) |
| +12VB | 7 A (84 W) | 8 A (96 W) | 9 A (108 W) | 10 A (120 W) | 11 A (132 W) |
| +5V | 2 A (10 W) | 2.5 A (12.5 W) | 2.5 A (12.5 W) | 3 A (15 W) | 3 A (15 W) |
| +3.3 V | 2 A (6.6 W) | 2.5 A (8.25 W) | 2.5 A (8.25 W) | 3 A (9.9 W) | 3 A (9.9 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (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 | 198.7 W | 223.5 W | 246.5 W | 270.9 W | 293.5 W |
| % Max Load | 36.1% | 40.6% | 44.8% | 49.3% | 53.4% |
| Room Temp. | 43.2° C | 44.2° C | 45.2° C | 46.5° C | 45.4° C |
| PSU Temp. | 46.0° C | 46.7° C | 47.6° C | 48.9° C | 49.9° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 259.1 W | 290.4 W | 318.4 W | 349.4 W | 378.6 W |
| Efficiency | 76.7% | 77.0% | 77.4% | 77.5% | 77.5% |
| AC Voltage | 114.6 V | 114.1 V | 113.6 V | 113.1 V | 113.3 V |
| Power Factor | 0.679 | 0.685 | 0.687 | 0.693 | 0.697 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
| Input | Test 11 | Test 12 | Test 13 | Test 14 | Test 15 |
| +12VA | 12 A (144 W) | 13 A (156 W) | 14 A (168 W) | 15 A (180 W) | 16 A (192 W) |
| +12VB | 11.75 A (141 W) | 12.75 A (153 W) | 13.5 A (162 W) | 14.5 A (174 W) | 15.5 A (186 W) |
| +5V | 3.5 A (17.5 W) | 3.5 A (17.5 W) | 4 A (20 W) | 4 A (20 W) | 4.5 A (22.5 W) |
| +3.3 V | 3.5 A (11.55 W) | 3.5 A (11.55 W) | 4 A (13.2 W) | 4 A (13.2 W) | 4.5 A (14.85 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (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 | 318.2 W | 340.5 W | 364.4 W | 386.9 W | 412.6 W |
| % Max Load | 57.9% | 61.9% | 66.3% | 70.3% | 75.0% |
| Room Temp. | 44.5° C | 46.6° C | 48.5° C | 45.7° C | 47.3° C |
| PSU Temp. | 46.9° C | 48.5° C | 50.6° C | 52.3° C | 54.3° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 411.5 W | 442.9 W | 474.0 W | 506.0 W | 543.0 W |
| Efficiency | 77.3% | 76.9% | 76.9% | 76.5% | 76.0% |
| AC Voltage | 113.4 V | 112.6 V | 112.7 V | 112.3 V | 112.1 V |
| Power Factor | 0.702 | 0.703 | 0.705 | 0.708 | 0.710 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
| Input | Test 16 | Test 17 | Test 18 | Test 19 | Test 20 |
| +12VA | 17 A (204 W) | 18 A (216 W) | 19 A (228 W) | 20 A (240 W) | 21 A (252 W) |
| +12VB | 16.5 A (198 W) | 17.25 A (207 W) | 18.5 A (222 W) | 19 A (228 W) | 20 A (240 W) |
| +5V | 4.5 A (22.5 W) | 5 A (25 W) | 5 A (25 W) | 5.5 A (27.5 W) | 5.5 A (27.5 W) |
| +3.3 V | 4.5 A (14.85 W) | 5 A (16.5 W) | 5 A (16.5 W) |
5.5 A (18.15 W) | 5.5 A (18.15 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (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 | 435.4 W | 458.7 W | 484.3 W | 503.4 W | 549.4 W |
| % Max Load | 79.2% | 83.4% | 88.1% | 91.5% | 99.9% |
| Room Temp. | 44.3° C | 47.1° C | 44.8° C | 45.5° C | 49.4° C |
| PSU Temp. | 50.9° C | 54.2° C | 46.7° C | 47.0° C | 51.2° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Fail on +12 V |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 576.0 W | 613.0 W | 651.0 W | 688.0 W | Fail |
| Efficiency | 75.6% | 74.8% | 74.4% | 73.2% | Fail |
| AC Voltage | 111.2 V | 110.8 V | 110.5 V | 110.1 V | Fail |
| Power Factor | 0.713 | 0.715 | 0.717 | 0.720 | Fail |
| Final Result | Pass | Pass | Pass | Pass | Fail |
Cooler Master eXtreme Power Plus 550 W burned while we tried to pull 550 W from it at high temperatures.
Efficiency was always below 80%, varying between 73.2% and 77.5%, depending on the load.
Voltages were always within the allowed range.
And noise and ripple levels were always low. Below we publish the results for the test 20 (550 W), however it is important to notice that noise levels jumped from the ultra-low 25.2 mV at +12VA on test 19 to 78.4 mV on test 20. The same thing happened with the other outputs (noise level at +5 V jumped from 18.8 mV to 43.6 mV, for example). The maximum allowed is 120 mV on +12 V outputs and 50 mV on +3.3 V and +5 V outputs. All numbers are peak-to-peak figures.
Figure 15: +12VA input from load tester at 549.4 W (78.4 mV).
Figure 16: +12VB input from load tester at 549.4 W (88.2 mV).
Figure 17: +5 V rail with power supply delivering 549.4 W (43.6 mV).
Figure 18: +3.3 V rail with power supply delivering 549.4 W (12.2 mV).