Seasonic X-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 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.
The +12V1 and +12V2 inputs listed below are the two +12 V independent inputs from our load tester and since this power supply has a single-rail design they were both connected to the power supply single +12 V rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12V1 | 5 A (60 W) | 10 A (120 W) | 15 A (180 W) | 20 A (240 W) | 24 A (288 W) |
| +12V2 | 5 A (60 W) | 10 A (120 W) | 14 A (168 W) | 19 A (240 W) | 24 A (288 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 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 | 141.5 W | 271.4 W | 398.9 W | 537.5 W | 662.9 W |
| % Max Load | 21.8% | 41.8% | 61.4% | 82.7% | 102.0% |
| Room Temp. | 47.8° C | 46.2° C | 46.9° C | 48.5° C | 47.6° C |
| PSU Temp. | 53.5° C | 53.5° C | 54.7° C | 57.1° C | 60.2° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 160.2 W | 299.1 W | 442.6 W | 604.0 W | 756.0 W |
| Efficiency | 88.3% | 90.7% | 90.1% | 89.0% | 87.7% |
| AC Voltage | 112.4 V | 110.5 V | 109.3 V | 107.4 V | 106.3 V |
| Power Factor | 0.984 | 0.997 | 0.992 | 0.994 | 0.995 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
What a power supply! What a power supply! You will get efficiency of at least 90% if you pull between 40% and 60% from its labeled load (between 260 W and 390 W). At 80% load (520 W) efficiency was still extremely high at 89%. At light load (20%, i.e., 130 W) efficiency dropped to 88%, still a very high value. The lowest efficiency was achieved with the power supply delivering its full 650 W, at 87.7%, a value far from being low!
It is always good to remember that we test power supplies at very high temperatures (between 45° C and 50° C). Since efficiency drops with temperature, these results are even more impressive when you think about them, especially because 80 Plus certification is achieved with a room temperature of half of what we used (23° C).
Voltage regulation was another highlight from X-Series 650 W. The manufacturer promises a voltage regulation tighter than what published on the ATX specification (3% vs. 5%). During our tests all outputs were within 3% from their nominal values, i.e., closer to their nominal values than required. This included the -12 V output, which usually doesn’t like to stay so close from its nominal value.
And to close the lid we have noise and ripple, which were extremely low all the time: noise level at +12 V was around 12.5% of the maximum allowed. Below you can see the results for test number five. As we always point out, the limits are 120 mV for +12 V and 50 mV for +5 V and +3.3 V and all numbers are peak-to-peak figures.
Figure 19: +12V1 input from load tester at 662.9 W (15.0 mV).
Figure 20: +12V2 input from load tester at 662.9 W (15.6 mV).
Figure 21: +5V rail with power supply delivering 662.9 W (17.2 mV).
Figure 22: +3.3 V rail with power supply delivering 662.9 W (15.2 mV).
Now let’s see if we could pull more than 650 W from this unit.
