SilverStone SFX Series SX700-LPT PSU Review

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SilverStone released a powerful new SFX-L unit that boasts 700W capacity, Platinum-rated efficiency, fully modular cabling, and a single +12V rail. The SX700-LPT is based on a Sirfa platform and promises quiet operation thanks to its 120mm fan.

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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
Test 12V 5V 3.3V 5VSB Pass/Fail
10% Load 9.5mV 7.4mV 10.8mV 4.6mV Pass
20% Load 14.6mV 10.4mV 14.1mV 5.8mV Pass
30% Load 15.0mV 10.9mV 16.5mV 6.7mV Pass
40% Load 16.4mV 11.1mV 17.1mV 7.7mV Pass
50% Load 21.3mV 13.9mV 21.0mV 7.9mV Pass
60% Load 24.7mV 15.7mV 23.1mV 9.2mV Pass
70% Load 29.9mV 15.9mV 26.8mV 9.3mV Pass
80% Load 35.7mV 19.6mV 28.7mV 12.7mV Pass
90% Load 42.8mV 20.0mV 28.8mV 13.6mV Pass
100% Load 52.8mV 23.5mV 36.2mV 15.9mV Pass
110% Load 479.3mV 46.3mV 46.4mV 43.4mV Fail
Cross-Load 1 18.2mV 16.5mV 29.1mV 5.9mV Pass
Cross-Load 2 55.6mV 21.8mV 28.6mV 17.5mV Pass

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.

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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

Aris Mpitziopoulos
Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

4 Comments Comment from the forums
  • JQB45
    Overpriced
    Reply
  • 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!
    Reply
  • 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.
    Reply
  • gadgety
    Great review. Thank you.
    Reply