Cougar CMX 700 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, the +12VA input was connected to the power supply +12V1 rail, while the +12VB input was connected to the power su
pply +12V2 rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 4.5 A (54 W) | 9.5 A (114 W) | 14.5 A (174 W) | 19 A (228 W) | 25.5 A (306 W) |
| +12VB | 4.5 A (54 W) | 9.5 A (114 W) | 14.5 A (174 W) | 19 A (228 W) | 25.5 A (306 W) |
| +5 V | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) | 11 A (55 W) |
| +3.3 V | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) | 11 A (36.3 W) |
| +5VSB | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 2.5 A (12.5 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 | 135.0 W | 269.8 W | 407.3 W | 528.4 W | 698.9 W |
| % Max Load | 19.3% | 38.5% | 58.2% | 75.5% | 99.8% |
| Room Temp. | 46.6° C | 45.9° C | 46.3° C | 48.0° C | 45.9° C |
| PSU Temp. | 49.2° C | 49.0° C | 49.2° C | 50.2° C | 52.1° C |
| Voltage Regulation | Pass | Pass | Pass | Failed at +5VSB | Failed at +3.3 V and +5VSB |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 159.7 W | 313.9 W | 479.2 W | 632.0 W | 867.0 W |
| Efficiency | 84.5% | 86.0% | 85.0% | 83.6% | 80.6% |
| AC Voltage | 114.9 V | 113.3 V | 111.5 V | 110.6 V | 108.8 V |
| Power Factor | 0.975 | 0.99 | 0.994 | 0.995 | 0.997 |
| Final Result | Pass | Pass | Pass | Fail | Fail |
The Cougar CMX 700 W can really deliver its labeled wattage at high temperatures.
Efficiency was high when we pulled between 20% and 80% of the labeled wattage (i.e., between 140 W and 560 W), ranging from 83.6 to 86.0 percent. At 700 W, efficiency dropped to 80.6%, which is below the 82% minimum required for the 80 Plus Bronze certification. As we always explain, the 80 Plus certification tests are conducted at a room temperature of only 23° C, while we test power supplies above 45° C, and efficiency drops with temperature.
This power supply has voltage regulation issues. During tests one and two, all positive voltages were within 3% of their nominal values, which is great. During test three the +5VSB output exited this tighter range, but was still inside the allowed 5% range, at +4.78 V. During test four, the +3.3 V also exited this tighter range, at +3.18 V, with the +5VSB dropping below the minimum allowed, at +4.72 V. And, during test five, the +12 V and +5 V outputs were outside the tighter 3% range, but still within the allowed 5% tolerance. (The +12VA input was at +11.63 V, the +12VB input was at +11.59 V, and the +5 V output was at +4.84 V.) However, the +3.3 V output dropped below the minimum allowed, at +3.11 V, and the +5VSB output dropped even more, to +4.65 V. 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.
Because of this issue, we requested a second sample to the manufacturer, since we may have received a defective unit. However, the second sample presented the exact same problem, showing that it is caused by a design flaw.
Noise and ripple levels, on the other hand, were always very 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 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 698.9 W (31.4 mV)
Figure 18: +12VB input from load tester during test five at 698.9 W (29.4 mV)
Figure 19: +5V rail during test five at 698.9 W (15 mV)
Figure 20: +3.3 V rail during test five at 698.9 W (22.4 mV)
Let’s see if we can pull more than 700 W from this unit.