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FSP Hydro X 450 Power Supply Review

After the Hydro G series, FSP decided to release a more affordable power supply called the Hydro X, which targets systems with lower energy needs. This PSU line consists of three units, and in this review we're testing the entry-level 450W model.

Efficiency, Temperature And Noise


Our efficiency testing procedure is detailed here.

Using the results from the previous page, we plotted a chart showing the Hydro X 450's efficiency at low loads, and loads from 10 to 110 percent of the PSU's maximum-rated capacity.

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The HGX450 is the second-most efficient PSU in this category. It loses only to Cooler Master's V450S, which performs phenomenally, especially under light loads. This new FSP platform is also efficient, and if its price drops to more realistic levels, it will be a good choice in the low wattage category.

Efficiency At Low Loads

In the following tests, we measure the efficiency of FSP's Hydro X 450 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 (RPM)Fan NoisePF/AC Volts
11.211A0.491A0.472A0.195A19.6672.07%69526.2 dB(A)0.892
22.450A0.981A0.976A0.391A39.7581.72%69526.2 dB(A)0.950
33.689A1.475A1.479A5.074A59.8385.14%69526.2 dB(A)0.970
44.920A1.983A1.955A0.785A79.7487.01%69526.2 dB(A)0.980

Under light loads, efficiency is very high. Even with only 20W of load it easily passes the 70% mark. Efficiency exceeds 80% in the rest of the tests, and during the last one it peaks at 87%. As we already mentioned, only the V450S manages to beat FSP's HGX450 here.

5VSB Efficiency

The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher with 100mA of load, 60 percent or higher with 250mA of load and 70 percent or higher with 1A or more of load.

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

Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
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FSP claims to enable a highly efficient 5VSB rail thanks to its advanced standby PWM controller, and indeed this is the case. In fact, efficiency is nothing less than amazing in each test, peaking at nearly 86% with 1A of load.

Power Consumption In Idle And Standby

Mode12V5V3.3V5VSBWattsPF/AC Volts
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In the table above, 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).

This unit has very low demands in standby mode, meaning that less energy gets wasted.

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 34 °C (93.2 °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 small, custom-made anechoic chamber with internals completely covered in sound-proofing material (be quiet! Noise Absorber kit). Background noise inside the chamber was below 18 dB(A) during testing, and the results were obtained with the PSU operating at 34 °C (93.2 °F) to 46 °C (114.8 °F) ambient temperature. 

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The following graph illustrates the fan's output noise over the PSU's entire operating range. The same conditions of the above graph apply to our measurements, though the ambient temperature was between at 28 °C (82.4 °F) to 30 °C (86 °F).  

Up to around 315W load, the PSU is inaudible, generating less than 25 dB(A). The noise remains low at higher loads, registering 31-34 dB(A). This is a quiet PSU overall.

Aris Mpitziopoulos
Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.