A Closer Look

The Zeus 850W power supply enclosure is painted matte black and uses a single 80mm exhaust fan on the front-side for cooling.  Previous Zeus models prior to the 750W have the fan located on the back like most other generic PSUs.  Mounting the fan on the front of the power supply, deep inside the PC enclosure helps isolate the fan noise and reduces the overall sound output from the PC.


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The SanCooler80 fan is made by Sanyo Denki (9A0812S413) and is rated for up to 42.4 CFM and 34 dBA at 3,400 rpm.  To help keep things quiet, the fan speed is automatically controlled by the internal component temperature (speeds up as the combined load and temperature increases).   


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The open grill on the back allows the exhaust air to exit the power supply with minimal resistance.  The Zeus 850W incorporates universal input (automatically adjusts the AC line voltage) and active PFC that adds to the units environmental friendliness.


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A small LED located next to the large power On-Off switch indicates the operational status of the power supply depending on its color.


  • Orange = Standby Mode
  • Green = Normal Operation
  • Red = Fault Condition

The Zeus 850W power supply supports ATX12V v2.2/EPS12V and is rated for a combined, continuous output power of 850 watts at up to 50°C ambient air temperature (internal case air temperature).  This is an important feature and one many generic power supplies don’t have.  Many less expensive power supplies rate their output capacity based on 25°C, which is not realistic.  If SilverStone rated the Zeus 850W this way it would be advertised as a 1,050W power supply. 


Specifications (from the SilverStone website)


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Quad +12V outputs


The Zeus ST85ZF PSU incorporates four 12V outputs (+12V1, +12V2, +12V3, and +12V4).  The following table shows the maximum rated current and what connectors are supplied by each output.


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Note 1: The maximum combined load for all four +12V outputs is 70A (840 watts).

Note 2:  The 4-pin +12V ATX adapter combines the +12V1 and +12V2 outputs when plugged into the 8-pin EPS 12V connector.


In the past, the majority of PC enthusiasts didn’t worry too much about their power supply — generic was frequently good enough.  For the most part those days are gone.  To operate a modern gaming rig or workstation today requires more thought and a greater investment to insure reliable operation.  If you think your new gaming PC will use between 300~400 watts of DC power then the PSU should be rated for at least 500~800 watts.  This will allow the power supply to operate at around 50%~60% of its rated capacity.  Operating in this range also places less stress on the unit and allows the power supply to operate with less noise (both audible noise and AC ripple noise on the DC outputs) and at higher efficiency.


If you are a gamer with one or more high-end video cards, then you will definitely need a high-quality, larger capacity power supply!  For example: BFG Tech recommends using a power supply that can deliver a minimum 26A +12V with their GeForce 7800/7900 video cards.  If you have two GeForce 7800/7900’s in SLI mode, then a minimum rating of 34A +12V is recommended.  That’s over 400 watts for just the two video cards.  And if you are planning to build a quad SLI setup along with a PhysX processor… the Zues 850W is ready!


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