A Closer Look

The OCZ ProXStream 1,000W power supply features a beautiful black-chrome, mirror-like finish on the enclosure.


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The back panel contains an 80mm cooling fan, power receptacle and a few stickers.  Noticeably missing is a power On-Off switch.  I suspect this was left out to help minimize the enclosure size.  The OCZ power supply incorporates universal AC input (automatically adjusts to the AC line voltage) so there is no little red voltage selector switch.


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The single 80mm cooling fan is made by Protechnic Electric (MGT8012UB-R25) who also manufactures high-quality fans for Zalman and Nexus.  According to their website, this is an ultra high speed fan that incorporates dual ball bearings.  To help minimize noise, the fan speed is automatically controlled by the internal component temperature (speeds up as the combined load and temperature increases).  As we will see later on, the OCZ ProXStream power supply was designed for performance, not silence. The slotted grill on the front and sides allows air to flow into the power supply with minimal restriction.


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The ProXStream 1kW PSU is rated for a combined, maximum output power of 1,000 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.  Some less expensive power supplies rate their output capacity based on 25°C, which is not realistic.    


Specifications for the OCZ ProXStream 1,000W


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Notice that the majority of the rated output capacity is supplied by the +12V section.

This is typical of most newer power supplies and a result of changes in the PC industry that more and more rely on +12V instead of +5V and +3.3V.


Quad +12V outputs


The ProXStream 1kW PSU incorporates four 12V outputs (+12V1, +12V2, +12V3, and +12V4).  As is the case in most PC power supplies, the four +12V outputs are all derived from a common +12V source and differentiated with individual current limiting circuits.  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 all four +12V outputs is 70A (840 watts).


Overall this looks to be like a good distribution.  My one concern is that the ProXStream PSU appears to still be using independent current limited rails for the +12V outputs instead of following the recent trend of going back to a single, high-power +12V output.  Even though the ProXStream has two of it’s four +12V outputs dedicated to PCI-E connectors, both the +12v3 and +12V4 outputs are supposed to be limited to 20A (240 watts).  This could be a potential problem for users with two 8800 video cards.  Some overclocked 8800’s can pull in excess of 300 watts each.  If the full 70A (840W) of +12V power were available across all cables/connectors this wouldn’t be an issue but with the two +12V outputs that are dedicated to powering video cards being current limited to 20A (240W) this could be a problem.


However, I found out through testing that both the +12V3 and +12V4 outputs are capable of delivering in excess of 300 watts.  The power supply shut down when either the +12V3 or +12V4 outputs went over 30A (360W).  So even though the literature says the maximum +12V current is 20A, the ProXStream appears to be capable of delivering a lot more than that (at least the one I have does).  This should be plenty of power for even an overclocked 8800.


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