OCZ StealthXStream 2 600 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. During our tests, the +12VA input was connected to the power supply +12V3 and +12V4 rails, while the +12VB input was connected to the power supply +12V1 and +12V2 rails.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 4 A (48 W) | 9 A (108 W) | 13 A (156 W) | 17.5 A (210 W) | 22.5 A (270 W) |
| +12VB | 4 A (48 W) | 9 A (108 W) | 13 A (156 W) | 17.5 A (210 W) | 22 A (264 W) |
| +5V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 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 | 114.9 W | 240.8 W | 353.7 W | 477.8 W | 602.4 W |
| % Max Load | 19.2% | 40.1% | 59.0% | 79.6% | 100.4% |
| Room Temp. | 45.2° C | 44.8° C | 45.0° C | 46.6° C | 45.4° C |
| PSU Temp. | 49.2° C | 48.8° C | 49.1° C | 50.0° C | 51.3° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 134.7 W | 277.2 W | 411.0 W | 565.1 W | 735.0 W |
| Efficiency | 85.3% | 86.9% | 86.1% | 84.6% | 82.0% |
| AC Voltage | 111.7 V | 113.2 V | 110.6 V | 108.5 V | 107.4 V |
| Power Factor | 0.974 | 0.985 | 0.991 | 0.994 | 0.995 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The StealthXStream 2 600 W can really deliver its labeled wattage at high temperatures.
We were really impressed by the new StealthXStream 2 600 W. During our tests it achieved efficiency compatible with the 80 Plus Bronze certification, even though this power supply officially has only the 80 Plus standard certification. Efficiency peaked at 87% with the power supply delivering 40% of its rated capacity (240 W).
Voltage regulation was another highlight of the product. During our tests all outputs were within 3% of their nominal values (including the -12 V output), meaning that they were closer to their nominal values than required (the ATX12V specification allows a tolerance of 5% for the positive voltages and 10% for the negative voltages).
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 17: +12VA input from load tester during test five at 602.4 W (34.4 mV)
Figure 18: +12VB input from load tester during test five at 602.4 W (33.4 mV)
Figure 19: +5V rail during test five at 602.4 W (12.2 mV)
Figure 20: +3.3 V rail during test five at 602.4 W (18.2 mV)
Let’s see if we can pull even more from the StealthXStream 2 600 W.