A Closer Look

The Element ST50EF-Plus power supply enclosure is painted matte black with lead-free paint, which along with other internal components, allows the unit to meet RoHS certification for using environmentally friendly materials.  The ST50EF-Plus uses a single fan on the bottom-side for cooling.  The 120mm Adda fan (AD1212HS-A71GL) incorporates sleeve bearings and is rated for up to 85.2 CFM and 39.1 dBA at 2,200 RPM. 

 

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The fan speed is automatically controlled by the internal component temperature (speeds up as the combined load and temperature increases).  The power supply incorporates universal input (automatically adjusts the AC line voltage) and active PFC that adds to the units environmental friendliness. 

 

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The open honey comb grill on the back allows exhaust air to exit the power supply with minimal resistance and less noise. 

 

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The Element ST50EF-Plus power supply is ATX12V v2.2 compliant and is rated for a combined, continuous output power of 500 watts at up to 50°C operating temperature.  That’s important as some less reputable manufacturers limit their power supply’s advertised capacity by specifying a lower operating temperature (typically an unrealistic 25°C) in the fine print.. 

 

Specifications (from the SilverStone website)

 

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The SilverStone ST50EF-Plus is nearly identical to the ST50EF unit except for a few minor tweaks to insure greater than 80% efficiency across all loading conditions (from 20% to 100% load).  The following table illustrates the differences between the two units.

 

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Dual +12V outputs

 

The Element ST50EF-Plus PSU incorporates two 12V outputs (+12V1 and +12V2).  The two outputs share a common +12V rail but are each current limited to a maximum of ~19A (which I verified during testing).  The following table shows the maximum rated current and what connectors are supplied by each output.

 

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Note: The maximum combined load for both +12V outputs is 36A (432 watts).  That means that 86% of the power supply’s rated 500W output is dedicated to the +12V outputs.  This illustrates a major shift that has occurred in the PC power supply industry over the past few years.  Less power is available on the +3.3V and +5V rails and more power is available on the +12V rail.  It used to be that the +3.3V and +5V rails were used to supply power to the CPU but when the Pentium 4 and Athlon 64 CPUs came along, motherboard manufactures started using the +12V rail to supply power to the CPU via onboard voltage regulators.

 

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