OCZ ZS Series 650 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 powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (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 this test, both inputs were connected to the power supply’s single +12 V rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 5 A (60 W) | 10 A (120 W) | 15 A (180 W) | 20 A (240 W) | 24 A (288 W) |
| +12VB | 5 A (60 W) | 10 A (120 W) | 15 A (180 W) | 20 A (240 W) | 24 A (288 W) |
| +5 V | 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 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 | 140.6 W | 269.1 W | 406.8 W | 542.9 W | 653.4 W |
| % Max Load | 21.6% | 41.4% | 62.6% | 83.5% | 100.5% |
| Room Temp. | 46.2° C | 45.2° C | 45.7° C | 47.3° C | 49.8° C |
| PSU Temp. | 45.4° C | 45.8° C | 46.3° C | 47.2° C | 48.9° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 166.1 W | 311.8 W | 475.4 W | 647.0 W | 796.0 W |
| Efficiency | 84.6% | 86.3% | 85.6% | 83.9% | 82.1% |
| AC Voltage | 113.5 V | 112.3 V | 110.0 V | 107.9 V | 105.3 V |
| Power Factor | 0.958 | 0.9 77 |
0.988 | 0.993 | 0.995 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The OCZ ZS Series 650 W passed our tests with flying colors. It can really deliver its labeled wattage at high temperatures.
Efficiency was between 84% and 86% when we pulled between 20% and 80% of the unit’s labeled power (i.e., between 130 W and 520 W). At full load (650 W), efficiency was at 82%. This is great to see, because several power supplies with 80 Plus Bronze certification that we’ve tested aren’t capable of sustaining 82% efficiency at high temperatures.
Voltages were closer to their nominal values (3% regulation) during all tests, which is terrific to see on a mainstream unit. The ATX12V specification says positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.
Noise and ripple levels were low at all times. 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 outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures.
Figure 17: +12VA input from load tester during test five at 653.4 W (51.4 mV)
Figure 18: +12VB input from load tester during test five at 653.4 W (51.2 mV)
Figure 19: +5V rail during test five at 653.4 W (13.4 mV)
Figure 20: +3.3 V rail during test five at 653.4 W (11.4 mV)
Let’s see if we can pull more than 650 W from this unit.