Skip to main content

BitFenix Formula Gold 450W PSU Review: Compact, Efficient, And Near-Silent

Efficiency, Temperature & Noise

Efficiency

Our efficiency testing procedure is detailed here.

Using results from the previous page, we plotted a chart showing the BF450G’s efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.

Image 1 of 4

Image 2 of 4

Image 3 of 4

Image 4 of 4

The BF450G is highly efficient under both light and normal loads.

Efficiency At Low Loads

In the following tests, we measure the BF450G'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 SpeedPSU NoisePF/AC Volts
11.204A0.496A0.478A0.196A19.52173.167%537 RPM10.3 dB(A)0.828
11.981V5.045V3.335V5.104V26.680115.35V
22.475A0.992A0.990A0.393A39.95882.931%537 RPM10.3 dB(A)0.923
11.980V5.044V3.334V5.097V48.182115.33V
33.679A1.487A1.470A5.089A59.46885.816%537 RPM10.3 dB(A)0.953
11.978V5.043V3.334V5.089V69.297115.30V
44.950A1.982A1.980A0.787A79.87087.881%537 RPM10.3 dB(A)0.968
11.975V5.043V3.333V5.082V90.884115.27V

We measured high efficiency levels, simultaneously observing that the BF450G's fan was barely spinning, making it almost inaudible.

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
10.100A0.51275.405%0.050
5.113V0.679115.27V
20.250A1.27878.309%0.116
5.109V1.632115.27V
30.550A2.80779.609%0.224
5.102V3.526115.37V
41.000A5.09177.571%0.336
5.090V6.563115.38V
51.500A7.61577.459%0.404
5.076V9.831115.37V
62.500A12.62575.140%0.473
5.050V16.802115.36V

Image 1 of 2

Image 2 of 2

The 5VSB rail achieved decent efficiency, coming close to competing PSUs with similar capacity.

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
Idle12.011V5.046V3.336V5.112V6.8480.387
115.4V
Standby0.0470.004
115.4V
Image 1 of 2

Image 2 of 2

BitFenix's PSU used very little power in standby mode.

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 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 was actually much lower, but our sound meter’s microphone hit 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 30°C (86°F) to 32°C (89.6°F).  

Under normal operating temperatures, the BF450G's fan spun at its lowest speed through almost all of the PSU's operating range.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

  • 2Be_or_Not2Be
    Nice - I really like how quiet these models are running.

    Of course, it's also funny that the Formula Gold model is less noisy on average than its "Whisper" mate.
    Reply
  • Dark Lord of Tech
    Excellent , thanks Aris!
    Reply