Ripple and Noise Tests
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, the +12VA and +12VB 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||141.2 W||270.2 W||408.5 W||545.9 W||652.8 W|
|% Max Load||21.7%||41.6%||62.8%||84.0%||100.4%|
|Room Temp.||46.6° C||46.3° C||48.4° C||44.8° C||45.8°
|PSU Temp.||49.0° C||48.9° C||49.6° C||46.9° C||47.8° C|
|Ripple and Noise||Pass||Pass||Pass||Pass||Pass|
|AC Power||165.9 W||311.4 W||476.0 W||650.0 W||795.0 W|
|AC Voltage||115.5 V||113.6 V||111.9 V||111.5 V||109.6 V|
The OCZ ZT Series 650 W passed our tests with flying colors.
Efficiency was between 82.1% and 86.8% during our tests, perfectly matching the 80 Plus Bronze certification. As you know, there are several power supplies with the 80 Plus Bronze certification that can’t deliver 82% efficiency at full load under high temperatures.
Voltages were closer to their nominal values (3% regulation) during all tests, which is terrific. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.
Let’s discuss the ripple and noise levels on the next page.