XFX 850 W Black Edition 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 our tests they were connected to the single +12V rail from 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 (384 W) |
| +12V2 | 6 A (72 W) | 12 A (144 W) | 17 A (204 W) | 25 A (300 W) | 29 A (384 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 | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) |
| Total | 174.5 W | 351.6 W | 515.8 W | 690.1 W | 853.4 W |
| % Max Load | 20.5% | 41.4% | 60.7% | 81.2% | 100.4% |
| Room Temp. | 43.8° C | 43.9° C | 49.9° C | 48.4° C | 46.0° C |
| PSU Temp. | 44.2° C | 44.5° C | 49.8° C | 58.0° C | 46.3° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 201.0 W | 400.6 W | 593.0 W | 808.0 W | 1031.0 W |
| Efficiency | 86.8% | 87.8% | 87.0% | 85.4% | 83.0% |
| AC Voltage | 112.5 V | 110.5 V | 109.1 V | 107.7 V | 104.7 V |
| Power Factor | 0.963 | 0.971 | 0.977 | 0.977 | 0.982 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
XFX 850 W Black Edition achieved very high efficiency just like Seasonic M12D and S12D, achieving up to 87.8% during our tests. Efficiency dropped to 83% while the unit was delivering 850 W, but this is quite normal to happen and we can’t say that 83% is a bad number. It is important to keep in mind that 80 Plus says that this unit present efficiency of at least 85% when delivering 850 W. Our numbers are usually a couple of points below that because we test power supplies at a room temperature of at least 45° C, while 80 Plus test them at 23° C – the higher the temperature, the lower efficiency is.
Voltage stability was another highlight from XFX 850 W Black Edition, with all positive voltages inside 3% of their nominal values(i.e., voltages were closer to their nominal value than needed, as ATX spec allows voltages to be up to 5% from their nominal values, 10% for -12 V). The -12 V output was outside this range during test five, at -12.4 V, but still very close to its nominal value.
And finally we have noise and ripple, which were low all the time: noise level at +12 V was below 25% of the maximum allowed. 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 18: +12V1 input from load tester at 856.0 W (27.0 mV).
Figure 19: +12V2 input from load tester at 856.0 W (29.4 mV).
Figure 20: +5V rail with power supply delivering 856.0 W (11.0 mV).
Figure 21: +3.3 V rail with power supply delivering 856.0 W (19.4 mV).
Now let’s see if we could pull more than 850 W from this unit.