Enermax Liberty ECO 500 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.
+12V1 and +12V2 are the two independent +12V inputs from our load tester and during out tests the +12V1 input was connected to the power supply +12V1 (main motherboard cable) and +12V2 (peripheral power connectors and video card auxiliary power connector) rails, while the +12V2 input was connected to the power supply +12V1 rail (EPS12V connector).
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12V1 | 4 A (48 W) | 7 A (84 W) | 11 A (132 W) | 14.5 A (174 W) | 18 A (216 W) |
| +12V2 | 3 A (36 W) | 7 A (84 W) | 10 A (120 W) | 14 A (168 W) | 18 A (216 W) |
| +5V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 5 A (25 W) | 6 A (30 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 5 A (16.5 W) | 6 A (19.8 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 2.5 A (12.5 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 | 104.3 W | 197.8 W | 302.0 W | 402.8 W | 501.8 W |
| % Max Load | 20.9% | 39.6% | 60.4% | 80.6% | 100.4% |
| Room Temp. | 48.5° C | 47.9° C | 48.0° C | 48.8° C | 50.0° C |
| PSU Temp. | 51.7° C | 50.8° C | 50.7° C | 51.9° C | 52.7° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power (1) | 118 W | 222 W | 343 W | 467 W | 600 W |
| Efficiency (1) | 88.4% | 89.1% | 88.0% | 86.3% | 83.6% |
| AC Power (2) | 125.2 W | 233.5 W | 360.4 W | 488.4 W | 623.0 W |
| Efficiency (2) | 83.3% | 84.7% | 83.8% | 82.5% | 80.5% |
| AC Voltage | 111.6 V | 110.5 V | 108.8 V | 108.1 V | 106.6 V |
| Power Factor | 0.975 | 0.984 | 0.987 | 0.990 | 0.993 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
Updated 06/25/2009: We re-tested this power supply using our new GWInsteak GPM-8212 power meter, which is a precision instrument and provides accuracy of 0.2% and thus presenting the correct readings for AC power and efficiency (results marked as "2" on the table above; results marked as "1" were measured with our previous power meter from Brand Electronics, which isn’t so precise as you can see). We also added the numbers for AC voltage during our tests, an important number as efficiency is directly proportional to AC voltage (the higher AC voltage is, the higher efficiency is). Also, manufacturers usually announce efficiency at 230 V, which usually inflates efficiency numbers. We added power factor (PF) numbers as well. These numbers measure the efficiency of the power supply active PFC circuit. This number should be as close to 1 as possible. Under light load (20% load, i.e., 100 W), the active PFC circuit from this unit isn’t as good as when operating under higher loads, but 0.975 is still a good number.
This power supply could really deliver 500 W at 50° C, which is terrific.
Enermax Liberty ECO 500 W achieved very good efficiency during our tests. If you pull up to 60% of its maximum labeled capacity (300 W) you will have at least 83% efficiency, peaking 84.7% when you pull 40% of its labeled maximum power (200 W). If you pull 80% of its labeled capacity (400 W) efficiency drops to 82.5%, still a good. At 100% load (500 W) efficiency dropped a lot, but was still above the 80% mark, at 80.5%.
So Liberty ECO series has a far better performance than the old Liberty DXX series. Enermax PRO82+ and MODU82+ series continue have an even higher efficiency, but they are more expensive.
Voltage regulation was also excellent, with all voltages within 3% from their nominal values – better than what is defined by ATX standard, which says they must be within 5% their nominal values. The exception was -12 V, which was however still within 5% from its nominal value (the tolerance for this particular output is 10%).
Noise and ripple levels were another highlight from this product, achieving values far below the maximum allowed – noise level at +12 V outputs was only at ¼ of the maximum allowed, while noise level at +5 V and +3.3 V was less than 2/5 the maximum allowed. Below you can see the noise and ripple levels during test number five, when the unit was delivering 501.8 W. Just to remember, the maximum allowed is 120 mV for the 12 V outputs and 50 mV for +5 V and +3.3 V outputs. All values are peak-to-peak.
Figure 16: Noise level at +12V1 with the reviewed power supply delivering 501.8 W (34 mV).
Figure 17: Noise level at +12V2 with the reviewed power supply delivering 501.8 W (34.4 mV).
Figure 18: Noise level at +5 V with the reviewed power supply delivering 501.8 W (19.6 mV).
Figure 19: Noise level at +3.3 V with the reviewed power supply delivering 501.8 W (14.6 mV).
Now let’s see if we can pull even more power from Liberty ECO 500 W.