ASUS P-50GA 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.
The +12V1 and +12V2 inputs listed below are the two +12 V independent inputs from our load tester and during all tests the +12V1 input was connected to the power supply +12V1 and +12V3 rails while the +12V2 input was connected to the power supply +12V2 rail.
| 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 | 193.3 W | 294.8 W | 391.8 W | 487.2 W | |
| % Max Load | 20.5% | 38.7% | 59.0% | 78.4% | 97.4% |
| Room Temp. | 47.7° C | 46.9° C | 47.0° C | 48.5° C | 45.4° C |
| PSU Temp. | 49.8° C | 49.2° C | 49.3° C | 52.0° C | 51.0° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 129.6 W | 238.6 W | 369.1 W | 501.0 W | 645.0 W |
| Efficiency | 79.2% | 81.0% | 79.9% | 78.2% | 75.5% |
| AC Voltage | 109.9 V | 108.1 V | 106.3 V | 106.1 V | 104.3 V |
| Power Factor | 0.989 | 0.995 | 0.996 | 0.997 | 0.998 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
ASUS P-50GA can really deliver 500 W at 45° C. The problem is that wattage isn’t everything and P-50GA presents efficiency below 80% almost all times, and this explains why this power supply isn’t 80 Plus-certified.
Voltages were always inside the 5% tolerance set by ATX specification (10% for -12 V) and presented low noise and ripple levels. 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 15: +12V1 input from load tester at 487.2 W (46.6 mV).
Figure 16: +12V2 input from load tester at 487.2 W (46.8 mV).
Figure 17: +5V rail with power supply delivering 487.2 W (12.8 mV).
Figure 18: +3.3 V rail with power supply delivering 487.2 W (12.2 mV).
Let’s see if we could pull more than 500 W from the reviewed unit.