Load Regulation, Hold-Up Time, And Inrush Current
To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units.
Primary Rails And 5VSB Load Regulation
Load Regulation testing is detailed here.
Our hold-up time tests are described in detail here.
Besides a very low hold-up time result, we also stumble upon a false power-good signal. That's very disappointing.
For details on our inrush current testing, please click here.
Observed inrush current is very high, especially with 115 V input.
Load Regulation And Efficiency Measurements
The first set of tests reveals the voltage rails' stability and SX700-LPT's efficiency. The applied load equals (approximately) 10 to 110 percent of the maximum load the supply can handle, in increments of 10 percentage points.
We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.
|Test #||12V||5V||3.3V||5VSB||DC/AC (Watts)||Efficiency||Fan Speed||Fan Noise||Temps (In/Out)||PF/AC Volts|
|1||3.945A||1.974A||1.959A||0.989A||69.72||87.24%||0 RPM||0 dB(A)||50.54°C||0.972|
|2||8.924A||2.959A||2.940A||1.195A||139.68||90.71%||0 RPM||0 dB(A)||51.75°C||0.990|
|3||14.277A||3.474A||3.453A||1.400A||209.88||90.94%||1650 RPM||38.4 dB(A)||40.94°C||0.995|
|4||19.625A||3.974A||3.936A||1.605A||279.75||91.48%||1660 RPM||38.5 dB(A)||41.48°C||0.997|
|5||24.639A||4.978A||4.925A||1.809A||349.71||91.41%||1700 RPM||39.0 dB(A)||41.93°C||0.998|
|6||29.673A||5.992A||5.914A||2.016A||419.62||91.05%||1770 RPM||39.6 dB(A)||42.88°C||0.998|
|7||34.712A||7.011A||6.905A||2.225A||489.62||90.63%||1805 RPM||40.3 dB(A)||44.08°C||0.998|
|8||39.770A||8.032A||7.896A||2.437A||559.56||90.07%||1860 RPM||41.3 dB(A)||44.26°C||0.999|
|9||45.275A||8.550A||8.417A||2.440A||629.59||89.49%||1885 RPM||41.6 dB(A)||45.42°C||0.999|
|10||50.537A||9.075A||8.911A||3.075A||699.49||88.78%||1885 RPM||41.6 dB(A)||45.57°C||0.999|
|11||56.319A||9.087A||8.935A||3.078A||769.22||84.73%||1885 RPM||41.6 dB(A)||46.19°C||0.999|
|CL1||0.101A||14.024A||14.005A||0.000A||118.84||82.80%||1885 RPM||41.6 dB(A)||45.95°C||0.990|
|CL2||58.282A||1.003A||1.003A||1.002A||716.90||89.37%||1885 RPM||41.6 dB(A)||46.07°C||0.999|
Load regulation on the +12V rail is tight enough, although nowhere close to the performance of Corsair's SFX family or Lian Li's similar PE-750, which uses a platform provided by Enhance Electronics. The 5V rail demonstrates average load regulation, the 5VSB rail is pretty loose, and the 3.3V rail surprises us by registering the best load regulation among all competing units.
As far as efficiency goes, the 20% load requirement is met. SilverStone's SX700-LPT comes close enough to the mid- and full-load requirements to get a pass from us given our high-temp testing methodology.
The semi-passive mode looks like it works normally since, during the CL1 test when the load is low, the fan stays active and at full speed due to high temperatures inside the PSU. We certainly wouldn't call the fan quiet in that case; it starts at 1650 RPM. Of course, this has to do with the very tough conditions inside our hotbox.