Seasonic Prime Ultra Platinum 1000W PSU Review

Efficiency, Temperature & Noise


Our efficiency testing procedure is detailed here.

Using results from the previous page, we plotted a chart showing the SSR-1000PD Ultra's efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.

We record top efficiency scores under both light and normal loads.

Efficiency At Low Loads

In the following tests, we measure the SSR-1000PD Ultra'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
11.191A0.490A0.474A0.196A19.64073.754%0 RPM
<6.0 dB(A)
22.410A0.988A0.985A0.396A39.79983.357%0 RPM<6.0 dB(A)0.918
33.624A1.486A1.493A5.016A59.88887.253%0 RPM<6.0 dB(A)0.951
44.833A1.983A1.973A0.796A79.81589.205%0 RPM<6.0 dB(A)0.971

Under light loads, the SSR-1000PD Ultra is highly efficient. It's also very quiet, since the semi-passive mode is enabled by default, keeping the fan from running. 

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 achieves high efficiency levels, even under light loads.

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

This PSU's power consumption at idle is very low.

Fan RPM, Delta Temperature, And Output Noise

Our mixed noise testing is described in detail here.

The first 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 47°C (116.6°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 47°C (116.6°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).  

Seasonic's semi-passive mode lasts up to 300W with a very small break just above. Beyond that point, the fan goes crazy, spinning up to full speed. With more than 880W load at +12V, the fan enters the 40-45 dB(A) region. Of course, this is quite noisy. Then again, the PSU endures quite a bit of stress, so it's natural for the fan to try dealing with that thermal load. 

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  • Th_Redman
    I notice you didn't give it an award rating...what gives, if you present it with such high praise?
  • Aris_Mp
    It has an award. It is just not shown, yet :)
  • Kennyy Evony
    Lets all hope it doesn't kill your motherboard and all components like my SeaSonic did while only operating 1 year under light workloads. No matter how much change they make to PSU I would not trust a brand that would allow catastrophic results in using their products AND not accept responsibility for the loss.