Cooler Master Silent Pro M 850 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 +12V1 and +12V2 inputs listed below are the two +12 V independent inputs from our load tester and during this test they were connected to the single +12V rail provided by the power supply.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12V1 | 6 A (72 W) | 13 A (156 W) | 20 A (240 W) | 25 A (300 W) | 29 A (348 W) |
| +12V2 | 6 A (72 W) | 12 A (144 W) | 17 A (204 W) | 25 A (300 W) | 29 A (348 W) |
| +5V | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) | 16 A (80 W) |
| +3.3 V | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) | 16 A (52.8 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 | 0.3 A (3.6 W) | 0.3 A (3.6 W) | 0.3 A (3.6 W) | 0.3 A (3.6 W) | 0.3 A (3.6 W) |
| Total | 166.4 W | 337.0 W | 493.9 W | 668.8 W | 818.8 W |
| % Max Load | 19.6% | 39.6% | 58.1% | 78.7% | 96.3% |
| Room Temp. | 47.7° C | 47.3° C | 46.9° C | 49.5° C | 47.1° C |
| PSU Temp. | 48.2° C | 49.3° C | 46.0° C | 52.2° C | 56.0° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 194.7 W | 388.3 W | 573.6 W | 781.0 W | 994.0 W |
| Efficiency | 85.5% | 86.8% | 86.1% | 85.6% | 82.4% |
| AC Voltage | 115.2 V | 113.2 V | 111.1 V | 109.6 V | 106.4 V |
| Power Factor | 0.978 | 0.984 | 0.991 | 0.993 | 0.995 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
Cooler Master Silent Pro M 850 W achieved very high efficiency when we pulled between 20% and 80% from its labeled capacity (i.e., between 170 W and 680 W), between 85.5% and 86.8%. If you pay close attention you will see that for test five the unit was delivering a little bit below its maximum capacity (820 W), situation where efficiency was not very high but still above the 80%, perfectly matching the 80 Plus Bronze certification achieved by this unit (82% minimum at full load and 85% minimum at typical, i.e., 50%, load).
Voltages were within the allowed range, the same happening with noise and ripple. Below you can see the results for test number five. As we always point out, the limits are 120 mV for +12 V and 50 mV for +5 V and +3.3 V and all numbers are peak-to-peak figures.
Figure 16: +12V1 input from load tester at 818.8 W (39.2 mV).
Figure 17: +12V2 input from load tester at 818.8 W (48.8 mV).
Figure 18: +5V rail with power supply delivering 818.8 W (21.4 mV).
Figure 19: +3.3 V rail with power supply delivering 818.8 W (14.4 mV).
Now let’s see if we could pull more than 850 W from this unit.