Rosewill Libertas 800 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 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. 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, which during our test were connected to the power supply’s single +12 V rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 5.5 A (66 W) | 12 A (144 W) | 18.5 A (222 W) | 23 A (276 W) | 29 A (348 W) |
| +12VB | 5.5 A (66 W) | 11 A (132 W) | 16 A (192 W) | 23 A (276 W) | 29 A (348 W) |
| +5V | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) | 10 A (50 W) |
| +3.3 V | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) | 10 A (33 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 | 161.5 W | 325.9 W | 483.3 W | 637.1 W | 799.4 W |
| % Max Load | 20.2% | 40.7% | 60.4% | 79.6% | 99.9% |
| Room Temp. | 46.4° C | 45.2° C | 44.4° C | 45.2° C | 49.5° C |
| PSU Temp. | 45.9° C | 46.3° C | 46.5° C | 47.9° C | 51.4° C |
| Voltage Stability | Pass | Pass | Pass | Failed on +5 V | Failed on +5 V |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 186.9 W | 370.9 W | 558.0 W | 755.0 W | 974.0 W |
| Efficiency | 86.4% | 87.9% | 86.6% | 84.4% | 82.1% |
| AC Voltage | 108.3 V | 106.4 V | 104.1 V | 102.2 V | 99.6 V |
| Power Factor | 0.993 | 0.996 | 0.996 | 0.996 | 0.996 |
| Final Result | Pass | Pass | Pass | Fail | Fail |
The Rosewill Libertas 800 W can really deliver its labeled wattage at high temperatures.
Efficiency was high, peaking 88% during test two (320 W). At full load the reviewed power supply achieved 82.1% efficiency, and Rosewill did a really good thing in downgrading this unit from 80 Plus Gold to 80 Plus Bronze. In a world full of companies trying to deceive consumers, it is always nice to see a company being honest.
The problem with the Libertas 800 W is that the +5 V output presented a voltage below the minimum allowed (4.75 V) during tests four (4.67 V) and five (4.61 V), a problem that can make your computer unstable.
Noise and ripple levels were always low. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for +12 V and -12 V, and 50 mV for +5 V and +3.3 V. All values are peak-to-peak figures.
Figure 19: +12VA input from load tester during test five at 799.4 W (39.8 mV)
Figure 20: +12VB input from load tester during test five at 799.4 W (39.8 mV)
Figure 21: +5V rail during test five at 799.4 W (26.2 mV)
Figure 22: +3.3 V rail during test five at 799.4 W (22.6 mV)
Let’s see if we can pull even more from the Rosewill Libertas 800 W.