OCZ Fatal1ty 750 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 +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During our review +12VA input was connected to the power supply +12V1 and +12V3 rails while the +12VB input was connected to the power supply +12V2 and +12V3 rails.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 5 A (60 W) | 11 A (132 W) | 16 A (192 W) | 22 A (264 W) | 27 A (324 W) |
| +12VB | 5 A (60 W) | 10 A (120 W) | 16 A (192 W) | 21 A (252 W) | 27 A (324 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 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 | 149.3 W | 300.4 W | 450.2 W | 598.3 W | 748.8 W |
| % Max Load | 19.9% | 40.1% | 60.0% | 79.8% | 99.8% |
| Room Temp. | 45.1° C | 45.7° C | 48.2° C | 44.2° C | 48.8° C |
| PSU Temp. | 44.3° C | 44.7° C | 45.8° C | 44.5° C | 47.6° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 177.9 W | 352.1 W | 532.6 W | 720.0 W | 918.0 W |
| Efficiency | 83.9% | 85.3% | 84.5% | 83.1% | 81.6% |
| AC Voltage | 112.1 V | 109.4 V | 106.2 V | 104.0 V | 103.3 V |
| Power Factor | 0.947 | 0.979 | 0.989 | 0.993 | 0.995 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
OCZ Fatal1ty 750 W can really deliver its labeled power at high temperatures.
Efficiency was very good, being above 83% at all tests except when we pulled 750 W from the unit, when it dropped to 81.6%. Being an 80 Plus Bronze unit it should deliver 82% efficiency at full load, but if you follow our power supply reviews know that several times what is promised by 80 Plus isn’t achieved because they test power supplies at a room temperature of only 23° C and we test power supplies at a room temperature of at least 45° C (efficiency drops with temperature).
Voltage regulation was superb, with all 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). This includes the -12 V output, which usually doesn’t like to stay within a tolerance this tight.
And finally we have noise and ripple, which were low all the time. Below you can see the results for test number five. As we always point out, the limits are 120 mV for +12 V and -12 V outputs and 50 mV for +5 V, +3.3 V and +5VSB outputs, and all numbers are peak-to-peak figures.
Figure 17: +12VA input from load tester at 748.8 W (58.6 mV).
Figure 18: +12VB input from load tester at 748.8 W (50.0 mV).
Figure 19: +5V rail with power supply delivering 748.8 W (12.0 mV).
Figure 20: +3.3 V rail with power supply delivering 748.8 W (13.4 mV).
Now let’s see if we could pull more than 750 W from this unit.