Enermax Liberty DXX 500W 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 six 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. This was the same load pattern we used for other 500 W power supplies we’ve tested recently like Antec EarthWatts 500 W.
For the 100% load test we used two patterns. On the first one, test number five, we respected the maximum combined limit for the two +12 V rails printed on the power supply label (384 W). In order to respect this limit, however, we were testing the power supply with more current on the +5 V and +3.3 V lines than we wanted. So we included a sixth pattern also pulling 500 W from Liberty DXX 500 W but pulling more current from +12 V and less current from +5 V and +3.3 V, using the same pattern used on the test of the abovementioned power supply from Antec, but pulling more current (and thus power) that the two +12 V rails could officially deliver together.
In the table below we list the load patterns we used and the results for each load.
+12V2 is the second +12 V input from our load tester and was connected to the power supply EPS12V connector. Since on this unit the only device connected to its +12V2 rail is really the EPS12V connector, on this review +12V1 and +12V2 on the tables and graphs below really represent the +12V1 and the +12V2 rails from the power supply.
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.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 | Test 6 |
| +12V1 | 4 A (48 W) | 8 A (96 W) | 11 A (132 W) | 14 A (168 W) | 16 A (192 W) | 17 A (204 W) |
| +12V2 | 3 A (36 W) | 6 A (72 W) | 10 A (120 W) | 14 A (168 W) | 16 A (192 W) | 17 A (204 W) |
| +5V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 12 A (60 W) | 9 A (45 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 11 A (36.3 W) | 9 A (29.7 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 3 A (15 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) | 0.6 A (7.2 W) | 0.6 A (7.2 W) |
| Total | 103.9 W | 195.6 W | 297.1 W | 397.9 W | 499.7 W | 499.1 W |
| % Max Load | 20.8% | 39.1% | 59.4% | 79.6% | 99.9% | 99.8% |
| Room Temp. | 45.2° C | 48.6° C | 46.° C | 45.4° C | 48.5° C | 47.5° C |
| PSU Temp. | 50.3° C | 44.1° C | 50.8° C | 51.1° C | 56.3° C | 53.4° C |
| Result | Pass | Pass | Pass | Pass | Pass | Pass |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass | Pass |
| AC Power | 129 W | 237 W | 366 W | 510 W | 657 W | 656 W |
| Efficiency | 80.5% | 82.5% | 81.2% | 78.0% | 76.1% | 76.1% |
The main problem with this power supply is efficiency, as you can see. It could only maintain efficiency above 80% on tests one (20% load or 104 W), two (40% load or 196 W) and three (60% load or 297 W). Just to remember, on Corsair VX450W and Antec EarthWatts 500 W (which are internally the same power supply) we saw an efficiency of 82% when the power supply was delivering 500 W and reaching above 85% on patterns one, two and three, where this unit from Enermax could only reach up to 82.5%.
Voltage regulation during all our tests was excellent, with all outputs within 3% of their nominal voltages – ATX specification defines that all outputs must be within 5% of their nominal voltages – except on +5 V, which was between 5.16 V and 5.17 V during all our tests. These numbers, however, are still inside the 5% margin that is set by the ATX spec for this output. Of course we always want to see values closer to the nominal voltage.
The main highlight from this product was noise and ripple, which were at a very low level. However when we moved from 80% load to 100% load the noise level at +12 V outputs almost doubled, jumping from 18 mV to 32
.4 mV at +12V1 and jumping from 21.4 mV to 34.4 mV at +12V2 (results for pattern number five). Even with this increase noise level was still very low and far away from the 120 mV limit. Noise level at +5 V was 16.2 mV and at +3.3 V was 15 mV, also for pattern number five. Pattern number six presented similar results, which are also similar to the results presented by Antec EarthWatts 500 W and Corsair VX450W.
Figure 19: Noise level at +12V1 with power supply delivering 500 W.
Figure 20: Noise level at +12V2 with power supply delivering 500 W.
Figure 21: Noise level at +5 V with power supply delivering 500 W.
Figure 22: Noise level at +3.3 V with power supply delivering 500 W.
Now let’s see if we could pull more power from this product.