SilverStone SFX Series SX700-LPT PSU Review

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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.

Hold-Up Time

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.

Inrush Current

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. 

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedFan NoiseTemps (In/Out)PF/AC Volts
13.945A1.974A1.959A0.989A69.7287.24%0 RPM0 dB(A)50.54°C0.972
28.924A2.959A2.940A1.195A139.6890.71%0 RPM0 dB(A)51.75°C0.990
314.277A3.474A3.453A1.400A209.8890.94%1650 RPM38.4 dB(A)40.94°C0.995
419.625A3.974A3.936A1.605A279.7591.48%1660 RPM38.5 dB(A)41.48°C0.997
524.639A4.978A4.925A1.809A349.7191.41%1700 RPM39.0 dB(A)41.93°C0.998
629.673A5.992A5.914A2.016A419.6291.05%1770 RPM39.6 dB(A)42.88°C0.998
734.712A7.011A6.905A2.225A489.6290.63%1805 RPM40.3 dB(A)44.08°C0.998
839.770A8.032A7.896A2.437A559.5690.07%1860 RPM41.3 dB(A)44.26°C0.999
945.275A8.550A8.417A2.440A629.5989.49%1885 RPM41.6 dB(A)45.42°C0.999
1050.537A9.075A8.911A3.075A699.4988.78%1885 RPM41.6 dB(A)45.57°C0.999
1156.319A9.087A8.935A3.078A769.2284.73%1885 RPM41.6 dB(A)46.19°C0.999
CL10.101A14.024A14.005A0.000A118.8482.80%1885 RPM41.6 dB(A)45.95°C0.990
CL258.282A1.003A1.003A1.002A716.9089.37%1885 RPM41.6 dB(A)46.07°C0.999

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.

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • JQB45
  • powernod
    Purely disappointing!!.
    A permanent flaw (false power-good signal), combined with a periodical flaw (far out of specs ripple if this unit gets overloaded), are more than enough evidence in order for me to conclude that this PSU is a potential danger for the rest of the hardware!!.
    Once more, thanks for the great review Aris!
  • basroil
    I looked at the internals first, and from that assumed this thing would be an utter mess. Surprisingly it's only a mess... If it was rated as a 550W unit I would have just said the holdup time was disappointing, but as a 700W rated unit this thing goes in the junk list.

    And seriously, what were they thinking with that layout? One short and the thing will definitely fry and take down your circuit breaker with it. Considering the number of missed surface mount solder points, shorts are going to be likely.
  • gadgety
    Great review. Thank you.