PC Power & Cooling Silencer 750 Quad Power Supply Review
Overload 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 maximum capacity (actual percentage used listed under “% Max Load”), watching how the reviewed unit behaved 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. On the “Total” row we are using the real amount of power being delivered, as measured by our load tester.
+12V2 is the second +12V input from our load tester and since the reviewed power supply uses a single-rail configuration this input was also connected to the +12V1 rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12V1 | 6 A (72 W) | 11.5 A (138 W) | 17 A (204 W) | 22 A (264 W) | 28 A (336 W) |
| +12V2 | 5 A (60 W) | 11 A (132 W) | 16 A (192 W) | 22 A (264 W) | 27 A (324 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 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) | 0.8 A (9.6 W) |
| Total | 6 A (72 W) | 11.5 A (138 W) | 17 A (204 W) | 22 A (264 W) | 28 A (336 W) |
| % Max Load | 20.2% | 40.1% | 59.3% | 79.2% | 99.5% |
| Room Temp. | 47.4° C | 47.9° C | 49.7° C | 50.1° C | 50.9° C |
| PSU Temp. | 50.1° C | 50.5° C | 51.6° C | 50.° C | 51.3° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 171 W | 337 W | 506 W | 694 W | 901 W |
| Efficiency | 88.8% | 89.1% | 87.9% | 85.6% | 82.8% |
| Final Result | Pass | Pass | Pass | Pass | Pass |
We were really impressed by this power supply.
First, it could really deliver its labeled power at 50° C.
Second, it achieved an outstanding efficiency, between 82.8% and 89.1%. In fact the only moment efficiency was below 85% was when the power supply was delivering its full load.
Third, voltage regulation was outstanding and during all our tests all outputs were within 3% of their nominal voltages – ATX specification defines that all outputs must be within 5% of their nominal voltages (10% for -12 V) –, including -12 V, which usually is not close to its nominal value, and also during our overload tests (see next page).
And fourth, even though noise and ripple weren’t the lowest we’ve seen around they were at levels below the average, which is excellent. With the reviewed power supply delivering 750 W of power noise level at +12 V outputs was around 50 mV, at +5 V was at 18.6 mV and at +3.3 V was at 20.4 mV. Just to remember, all values are peak-to-peak voltages and the maximum allowed set by ATX standard is 120 mV for +12 V and 50 mV for +5 V and +3.3 V.
Another thing we liked about this power supply was that noise didn’t increase with increase in load. Usually as we increase the power supply load noise also increases. Noise levels remained practically the same on our load tests.
Figure 16: Noise at +12V1 input from load tester at 750 W.
Figure 17: Noise at +12V2 input from load tester at 750 W.
Figure 18: Noise at +5 V input from load tester at 750 W.
Figure 19: Noise at +3.3 V input from load tester at 750 W.
Now let’s see if we could pull even more power from this unit.