be quiet! Dark Power Pro 10 850 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 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, we configured the power supply to use a single +12 V rail design, so both inputs were connected to the power supply’s single +12 V rail. (We connected the EPS12V connector to the +12VB input.)
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 6 A (72 W) | 13 A (156 W) | 19 A (228 W) | 25.5 A (306 W) | 32 A (384 W) |
| +12VB | 6 A (72 W) | 13 A (156 W) | 19 A (228 W) | 25.5 A (306 W) | 31.5 A (378 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 | 163.6 W | 341.9 W | 503.6 W | 675.7 W | 848.8 W |
| % Max Load | 19.2% | 40.2% | 59.2% | 79.5% | 99.9% |
| Room Temp. | 45.5° C | 45.0° C | 45.1° C | 46.7° C | 49.4° C |
| PSU Temp. | 46.5° C | 46.6° C | 47.0° C | 48.0° C | 49.8° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 181.9 W | 374.0 W | 554.5 W | 754.0 W | 963.0 W |
| Efficiency | 89.9% | 91.4% | 90.8% | 89.6% | 88.1% |
| AC Voltage | 113.9 V | 111.9 V | 109.3 V | 107.4 V | 105.1 V |
| Power Factor | 0.994 | 0.995 | 0.997 | 0.998 | 0.998 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The 80 Plus Platinum certification guarantees minimum efficiencies of 90% at 20% load, 92% at 50% load, and 89% at 100% load. In our tests, the be quiet! Dark Power Pro 10 850 W presented 89.9% efficiency at 20% load, matching the 80 Plus Platinum certification. We didn’t test this power supply at 50% load, but considering that we saw 91.4% efficiency at 40% load, we can assume that this unit is able to achieve 92% efficiency at 50% load. At full load, we saw 88.1% efficiency, one percentage point below the minimum advertised by the 80 Plus Platinum certification. However, we have to consider that during this test, the AC voltage dropped to 105 V, which is probably the culprit. Also, 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 with temperature.
All positive voltages were closer to their nominal values during all tests (3% voltage regulation). The -12 V output, however, got outside this tighter regulation during tests one (-11.42 V) and two (-11.55 V), but were 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.