Coolmax V-500 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.
Because we had no clue as to the real wattage of this power supply, we tested it differently. Starting from 85 W, we increased the load little by little until we could see the maximum amount of power we could extract from the reviewed unit.
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 | Test 6 |
| +12VA | 3 A (36 W) | 3.5 A (42 W) | 4.5 A (54 W) | 5.5 A (66 W) | 6.25 A (75 W) | 7.5 A (90 W) |
| +12VB | 2.5 A (30 W) | 3.25 A (39 W) | 4 A (48 W) | 5 A (60 W) | 6 A (72 W) | 7 A (84 W) |
| +5 V | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 A) | 1.5 A (7.5 A) | 2 A (10 W) | 2 A (10 W) |
| +3.3 V | 1 A (5 W) | 1 A (5 W) | 1.5 A (4.95 W) | 1.5 A (4.95 W) | 2 A (6.6 W) | 2 A (6.6 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (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) | 0.5 A (6 W) |
| Total | 90.6 W | 99.5 W | 124.4 W | 147.1 W | 171.9 W | 196.4 W |
| % Max Load | 18.1% | 19.9% | 24.9% | 29.4% | 34.4% | 39.3% |
| Room Temp. | 42.2° C | 41.6° C | 41.3° C | 41.2° C | 41.2° C | 40.2° C |
| PSU Temp. | 47.4° C | 46.2° C | 45.6° C | 45.3° C | 45.3° C | 44.7° C |
| Voltage Regulation | Pass | Pass | Pass | Failed on +5 V | Failed on +5 V | Failed on +5 V |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass | Pass |
| AC Power | 119.4 W | 130.4 W | 161.4 W | 191.5 W | 224.3 W | 260.4 W |
| Efficiency | 75.9% | 76.3% | 77.1% | 76.8% | 76.6% | 75.4% |
| AC Voltage | 115.6 V | 115.9 V | 115.0 V | 114.0 V | 114.6 V | 113.5 V |
| Power Factor | 0.649 | 0.652 | 0.658 | 0.662 | 0.665 | 0.668 |
| Final Result | Pass | Pass | Pass | Fail | Fail | Fail |
| Input | Test 7 | Test 8 | Test 9 | Test 10 | Test 11 | Test 12 |
| +12VA | 8.25 A (99 W) | 9.25 A (111 W) | 10 A (120 W) | 11 A (132 W) | 12 A (144 W) | 13 A (156 W) |
| +12VB | 8 A (96 W) | 9 A (108 W) | 10 A (120 W) | 11 A (132 W) | 11.75 A (141 W) | 12.75 A (153 W) |
| +5 V | 2.5 A (12.5 W) | 2.5 A (12.5 W) | 3 A (15 W) | 3 A (15 W) | 3.5 A (17.5 W) | 3.5 A (17.5 W) |
| +3.3 V | 2.5 A (8.25 W) | 2.5 A (8.25 W) | 3 A (9.9 W) | 3 A (9.9 W) | 3.5 A (11.55 W) | 3.5 A (11.55 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (5 W) | 1 A (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) | 0.5 A (6 W) |
| Total | 220.2 W | 240.8 W | 263.4 W | 282.9 W | 304.4 W | 329.4 W |
| % Max Load | 44.0% | 48.2% | 52.7% | 56.6% | 60.9% | 65.9% |
| Room Temp. | 40.6° C | 41.4° C | 42.3° C | 43.4° C | 44.3° C | 44.4° C |
| PSU Temp. | 45.3° C | 46.3° C | 47.5° C | 48.9° C | 50.7° C | 49.3° C |
| Voltage Regulation | Failed on +5 V | Failed on +5 V and +12 V | Failed on +5 V and +12 V | Failed on +5 V and +12 V | Failed on +5 V and +12 V | Failed on +5 V and +12 V |
| Ripple and Noise | Pass | Pass | Failed on +12 V | Failed on +12 V | Failed on +12 V and -12 V | Failed on +12 V, +5 V, and -12 V |
| AC Power | 296.0 W | 330.5 W | 370.6 W | 410.5 W | 456.0 W | 487.0 W |
| Efficiency | 74.4% | 72.9% | 71.1% | 68.9% | 66.8% | 67.6% |
| AC Voltage | 114.0 V | 114.2 V | 113.2 V | 112.8 V | 112.2 V | 112.2 V |
| Power Factor | 0.672 | 0.676 | 0.68 | 0.685 | 0.69 | 0.672 |
| Final Result | Fail | Fail | Fail | Fail | Fail | Fail |
The Coolmax V-500 is a piece of junk. We could only pull around 330 W from it. Above that the power supply burned.
Efficiency was always very low, between 66.8% and 77.1%. In fact, when we consider that power supplies achieve their peak efficiency when delivering around 50% of their maximum load, the Coolmax V-500 would be a 250 W unit, since its peak efficiency was achieved during test three, with the power supply delivering around 125 W.
Voltage regulation is one of the main issues with this unit. From test four (150 W) on, voltages were outside their proper range. The +5 V output failed on test four at +5.26 V (the maximum allowed is +5.25 V), increasing all the way to +5.39 V on test 12. The +12 V output failed from test eight (240 W) on, dropping to +11.38 V during this test (the minimum allowed is +11.40 V), decreasing to +10.99 V during test 12. 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 got above the proper level from test nine (260 W) on. During test 12, noise levels at the +12 V outputs were at 207 mV, at the +5 V outputs were at 60 mV, and at the -12 V outputs were 186 mV. 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.