Cold Test Results

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M  40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

The efficiency of the SilverStone SX700-LPT is excellent, meeting and surpassing the 80Plus Platinum guideline with an input voltage of 230V AC. Our instruments measured a maximum efficiency of 94.3% at 50% load and an average efficiency across the entire nominal load range (20% to 100% of the unit's capacity) of 92.5%. The low load efficiency of the PSU is outstanding as well, with a reading of 89.2% and 81.4% under 10% load and 5% load respectively.

The SX700-LPT sports a semi-fanless design, meaning that the fan will start only after the load is higher than 150W. Due to its densely packed design, the internal temperatures of the SX700-LPT rise sharply until the fan starts, but the internal temperatures drop down to reasonable levels once the fan is working. When operating in room temperature, the cooling fan is relatively tolerable with loads only up to 500 Watts. Beyond that point, the thin fan speeds up significantly in order to keep up with the cooling needs of the PSU, reaching above 44 dB(A) at maximum load, an uncomfortable noise level for casual use.

The SilverStone SX700-LPT SFX-L PSU Hot Test Results
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  • usernametaken76 - Friday, September 30, 2016 - link

    That's why there's a 120mm fan to keep it cool, and it simply loses efficiency at that temp, it doesn't shut down (unless it's actually overheating) or melt. I have one and I don't even hear the fan kick on - which it will automatically when it gets hot.
  • Samus - Saturday, October 1, 2016 - link

    My SFX PSU fan rarely ever comes on, because it doesn't even crack 30C when the system is at idle. It starts spinning after 20 minutes of web surfing. Same with my video card, 970 blower doesn't even run until I go into a game.
  • Alistair - Friday, September 30, 2016 - link

    I have bought two of Silverstone's sfx-L power supplies, both had problems with the fan. The PSU looks awesome, but the fan's 0rpm mode doesn't work right, or it randomly makes weird sounds (crunching, or rising beep tone sounds, never heard that coming out of a PSU before). Check newegg reviews you'll see people with similar problems.

    After giving up on them selling me a quality PSU, I bought the new Corsair SFX power supply, and it is awesome. Save yourself the trouble and buy the Corsair one. You'll thank me.
  • Alistair - Friday, September 30, 2016 - link

    Also get the Lian Li Q10 case. It can cool anything. Literally it is amazing cold in there even with one 120mm fan. I have a GTX 1080 and overclocked to max i5-6600K and it is cool with the fans set to 600rpm. I even fit the Noctua U12S in that case!!!
  • jdon - Thursday, October 6, 2016 - link

    Tony Ou from Silverstone posted about this on another forum, and there is a more recent version of the 700w PSU with updates to the fan controller that should make things a bit less awkward for lower usage scenarios. To differentiate updated SX700-LPTs, you have to check the serial number. Numbers starting with 1621 or earlier are the original ones while numbers starting with 1624 and after are updated units.
  • Gadgety - Wednesday, October 5, 2016 - link

    This or the LianLi PE-750? Opinions please
  • InterClaw - Thursday, October 6, 2016 - link

    Any news on the SX800-LTI announced at Computex?
  • waltercarroll - Monday, October 17, 2016 - link

    Usually power supplies are not that much effective and for pc normal use or gaming i am desperate to have such a thing so that my pc board is not at risk.

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