SilverStone SFX Series SX700-LPT PSU Review

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Ripple Measurements

To learn how we measure ripple, please click here.

The following table includes the ripple levels we measured on the SX700-LPT's rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V and 5VSB).

Swipe to scroll horizontally
10% Load9.5mV7.4mV10.8mV4.6mVPass
20% Load14.6mV10.4mV14.1mV5.8mVPass
30% Load15.0mV10.9mV16.5mV6.7mVPass
40% Load16.4mV11.1mV17.1mV7.7mVPass
50% Load21.3mV13.9mV21.0mV7.9mVPass
60% Load24.7mV15.7mV23.1mV9.2mVPass
70% Load29.9mV15.9mV26.8mV9.3mVPass
80% Load35.7mV19.6mV28.7mV12.7mVPass
90% Load42.8mV20.0mV28.8mV13.6mVPass
100% Load52.8mV23.5mV36.2mV15.9mVPass
110% Load479.3mV46.3mV46.4mV43.4mVFail
Cross-Load 118.2mV16.5mV29.1mV5.9mVPass
Cross-Load 255.6mV21.8mV28.6mV17.5mVPass

Ripple suppression at +12V is decent up to the full load test, but during our overload test (110% load) ripple goes out of control with almost 0.5V deviations! Such high ripple can easily damage other components inside of your PC. Despite the out-of-control +12V rail, the minor rails keep ripple in-spec during the overload test.

We should stress that SilverStone clearly states this unit's peak load is 750W and not the 770W we applied (following methodology that we use in every PSU review). In order to be fair, we also conducted an overload test with 750W load and didn't notice any ripple suppression problems at +12V. Apparently, 20W of additional load are enough to cause chaos.

Thanks to the higher efficiency and decreased thermal load of 230V input, ripple suppression with 110% load is normal.

Ripple Oscilloscope Screenshots

The following oscilloscope screenshots illustrate the AC ripple and noise registered on the main rails (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the screen, the bigger the ripple/noise. We set 0.01 V/Div (each vertical division/box equals 0.01 V) as the standard for all measurements.

Ripple At Full Load

Ripple At 105-Percent Load

Ripple At 110-Percent Load

Ripple At Cross-Load 1

Ripple At Cross-Load 2

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.