SilverStone SX800-LTI PSU Review

Efficiency, Temperature & Noise


Our efficiency testing procedure is detailed here.

Using results from the previous page, we plotted a chart showing the SX800-LTI's efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.

This is a highly efficient PSU. However, with 115V input, the efficiency gap is quite large under high loads compared to 230V input.

Lian Li's PE-750 looks to have the lead in our normal and light load tests. However, the overall efficiency rating, derived from thousands of possible load combinations, yields a small victory to the SilverStone PSU. Both units employ the same platform, so it'd be natural for them to demonstrate similar efficiency levels.

Efficiency At Low Loads

In the following tests, we measure the SX800-LTI's efficiency at loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dialed were 20, 40, 60, and 80W. This is important for representing when a PC is idle, with power-saving features turned on.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed
PSU Noise
PF/AC Volts
11.208A0.483A0.480A0.196A19.63875.697%0 RPM
<6.0 dB(A)
22.447A0.970A0.987A0.391A39.74982.575%0 RPM<6.0 dB(A)0.929
33.682A1.460A1.502A5.097A59.83587.414%0 RPM<6.0 dB(A)0.941
44.904A1.954A1.981A0.785A79.73490.573%0 RPM<6.0 dB(A)0.960

Under light loads, SilverStone's efficiency levels are very high. The SX800-LTI operates in passive mode at this point, so its noise output is below the measuring capabilities of our highly sensitive microphone.

5VSB Efficiency

The ATX specification, along with CEC, ErP Lot 3 2014 and ErP Lot 6 2010/2013, states that 5VSB standby supply efficiency should be as high as possible, recommending 75 percent or higher with 550mA, 1A, and 1.5A of load. The PSU should also achieve higher than 75% efficiency at 5VSB under full load, or with 3A if its max current output on this rail is higher than 3A.

We take six measurements: one each at 100, 250, 550, 1000, and 1500mA, and one with the full load the 5VSB rail can handle.

Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts

The 5VSB rail's efficiency is high, as you can see in the graphs and table above.

Power Consumption In Idle And Standby

In the table below, you'll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (powered on, but without any load on its rails), and the power consumption when the PSU is in standby mode (without any load, at 5VSB).

Mode12V5V3.3V5VSBWattsPF/AC Volts

Vampire power with 115V input is low. However, it rises notably with 230V.

Fan RPM, Delta Temperature, And Output Noise

Our mixed noise testing is described in detail here.

The chart below illustrates the cooling fan's speed (in RPM), and the delta between input and output temperature. The results were obtained at 37°C (98.6°F) to 46°C (114.8°F) ambient temperature.   

The next chart shows the cooling fan's speed (again, in RPM) and output noise. We measured acoustics from one meter away, inside a hemi-anechoic chamber. Background noise inside the chamber was below 6 dB(A) during testing (it's actually much lower, but our sound meter’s microphone hits its floor), and the results were obtained with the PSU operating at 37°C (98.6°F) to 46°C (114.8°F) ambient temperature.

The following graph illustrates the fan's output noise over the PSU's operating range. The same conditions of the above graph apply to our measurements, though the ambient temperature was between at 30°C (86°F) to 32°C (89.6°F).

SilverStone's passive mode doesn't last long: up to around 120W at +12V. Afterwards, with up to 500W load at +12V, the PSU lands within the 30-35 dB(A) range. Worst-case, the fan is quite loud, generating more than 45 dB(A) of noise. All in all, the fan profile could be looser given this PSU's high efficiency.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Create a new thread in the Reviews comments forum about this subject
Comment from the forums
    Your comment
  • shrapnel_indie
    I know a guy that used to work for SLM at one time in his life. On one of the products for the company brands owned, he could mod it (it was a musical instrument amplifier) for just a couple of pennies and could have saved the company large sums of money on warranty work and improve reliability. He proposed the change, and it was denied because it broke the price-point, and warranties would cover any issues anyway.

    When bean-counters run the show, products will suffer, just so the price-point isn't exceeded and (now days particularly, immediate) profits are maximized. Makes me wonder if Silverstone listened to their bean-counters a little too much.
  • Aris_Mp
    The thing I appreciate in SilverStone is that they didn't follow the marketing war in the warranty periods. For me it is really weird to see 10-12 years warranty in PSUs. Now with the mining craziness many companies are trying to find ways to get out of this.
  • seanwilson5274
    why did an ad leading to this article popped up automatically on my windows 10 screen? I don't like being spammed, and even less so, when it comes in as sneaky as this.
  • derekullo
    It is Tom's way of encouraging you to block ads.

    Custom Hosts File
    Adguard DNS

    Any of those 3 can make Toms ad free.
  • SilverStone Guy
    Anonymous said:
    When bean-counters run the show, products will suffer, just so the price-point isn't exceeded and (now days particularly, immediate) profits are maximized. Makes me wonder if Silverstone listened to their bean-counters a little too much.

    If bean-counters had their way, a PSU like this would have never been released in the first place! It's a very niche product that will not sell in significant quantities. Implementing sleeve bearing fan was not a cost-cutting move, it was out of necessity to keep the PSU noise low for the intended applications. At the time of development, FDB version of this fan was not yet available to us.