SilverStone Zeus ST65ZF 650W

Written by John Chen    Sunday, 06 November 2005 11:00
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We all know that reliable power supplies are a must when building a system.  Beefy power supplies, however, are not necessities, but a commodity.  There is no reason why you should use a 600W power supply in an average computer system.  400W of power from a reliable provider is more than enough, that is if you are not overclocking.  So when does a 600W+ power supply become useful?  A fully stacked server, high end gaming machine, or an overclocked rig will definitely need a robust power supply.  It is quite surprising how much power the CPU and GPU can eat up after some voltage increase and overclocking. 

SilverStone is slowly gaining reputation as a solid power supply provider.  Our previous encounter with their 520W solution was more than satisfactory and should be able to handle everything you throw at it.  SilverStone certainly did not stop there.  Their current flagship is 130W more beefier than the ST52F, resulting with a 650W rating. 

SilverStone ST65ZF Package

Much like all power supplies, the SilverStone Zeus ST65ZF comes with an AC adapter, user's manual, and some screws.  There is also an 8pin-to-4pin 12v adapter.  All power supplies now come with a 4pin 12v adapter for dedicated CPU power, but high wattage power supplies often provide an 8pin 12v adapter for high end workstation or server motherboards.  Instead of having two separate cables and adding more work into cable management, SilverStone made a single 8pin 12v cable and included an adapter.  This is not something dramatic, but it is good thinking.


SilverStone ST65ZF External

The ST65ZF is one heavy power supply and that is definitely a good thing.  A general rule for power supplies is that the heavier it is, the better.  The power supply deviates from the typical silver color and comes in an attractive gun metal finish.  Another general rule for power supplies is that the better cooling it receives, the better it performs.  The more wattage it provides, the hotter the internal components become.  If cooling becomes insufficient, the power supply starts to degrade a lot faster and provides unstable power, causing voltage rails to fluctuate.  That is why good cooling is a necessity for power supplies.  Surprisingly, the ST65ZF only comes with one 80mm fan for exhaust.  There are circular ventilation holes at the back of the PSU for natural case airflow, but another fan should have been added.  The fan is going to spin quite for in order to release the heat output of the internal components.



SilverStone ST65ZF Internal

As mentioned earlier, the power supply was quite heavy when I initially picked it up.  I also noticed that the PSU was not much bigger than a standard ATX power supply.  This only led me to believe that the components inside must be tightly packed.  After popping open the hood, my assumptions were true.  The ST65ZF is filled with components that covered every inch of space allowed.  The heatsinks used are exceptionally large and will be great to help with heat dissipation.  There is a special circuit board at the side just for different protection features. 




It wouldn't make much sense if a robust power supply only came with a few connectors.  SilverStone made sure that the ST65ZF fulfills all your needs.  There is a total of six 4pin Molex connectors with two 4pin floppy connectors are the end.  There are four SATA connectors for enthusiasts who like to stack up their hard drives and run insane amounts of storage.  As mentioned earlier, the 8pin 12v cable can be converted to the standard 4pin 12v connector.  One main marketing point of the ST65ZF is that it was the first 600W+ power supply to be certified by Nvidia for SLI.  Thus, it can only make sense for the PSU to come with two PCI-E connectors.  There is another connector that looks like the PCI-E connector, but that is for workstation video cards that also use the 3.3v rail.  The 24pin native ATX connector allows the extra 4 pins to be popped off for older motherboards that come with 20pin ATX connectors. 


Dual 12v rails on new power supplies are becoming quite common.  The ST65ZF comes with quad 12v rails!  This means that each additional rail helps reduce the stress when the demand becomes too high.  The four 12v rails add up to a whopping total of 55A!  But SilverStone specified that the combined amps for the 12v rails shall not exceed 42A.  Such a high division would only mean that the 3.3v and 5v rails are not extremely high.  The 3.3v comes with 33A, which is quite normal, and the 5v comes with 24A, which is a little lacking when compared to competitors. 

The ST65ZF comes with quite a few protections.

  • Over current protection
  • Under voltage protection
  • Over voltage protection
  • Short circuit
  • No load operation

The PSU is also rated with an efficiency of 75.8%.  The higher the percentage, the better.  The power supply efficiency means more of the electricity coming in from the outlet is being used, which means a less costly electricity bill.  75% is pretty decent for a power supply right now, but I have been seeing quite a few competitors providing up to 80%. 

As suspected, the single 80mm fan used for cooling does become rather loud when the load increases.  The fan speed is automatically adjusted by the power supply, but even the minimum 29 dBA measure is a tad loud.  Silent enthusiasts will definitely be a turned off.  Unfortunately, that is the kind of sacrifice you have to make sometimes.


Testing Setup and Results

Test Setup and Method:

  • Intel Pentium D 840
  • Asus P5WD2 Premium
  • ATI Radeon X800XT
  • 2 x 512MB OCZ Platinum PC2-8000
  • Hitachi 80GB SATA
  • Sony DVD-Rom
  • Floppy drive
  • 120mm Evercool
  • DLink 802.11b wireless NIC

Running Stock:

  • Intel Pentium D 840 3.2GHz -- 16 x 200FSB = 3.2GHz @ 1.4v
  • 2 x 512MB OCZ Platinum PC2-8000 -- 200FSB 3:4 266MHz @ 2.0v
  • ATI Radeon X800XT -- 500/500
  • FSB Termination Voltage -- 1.2v
  • ICH Chipset Voltage -- 1.05v
  • MCH Chipset Voltage -- 1.5v

Running Overclocked:

  • Intel Pentium D 840 3.2GHz -- 16 x 250FSB = 4.0GHz @ 1.4v
  • 2 x 512MB OCZ Platinum PC2-8000 -- 250FSB 1:2 500MHz @ 2.0v
  • ATI Radeon X800XT -- 540/540
  • FSB Termination Voltage -- 1.5v
  • ICH Chipset Voltage -- 1.2v
  • MCH Chipset Voltage -- 1.65v

Testing the power supply is a tedious task.  Like cooling products, the "proper" testing method is long and strenuous.  It involves high end equipment and testing materials that we simply cannot get our hands on.  A simple proper testing method would be to test the wattage draw from the AC outlet, voltage rail fluctuations, wattage fluctuations under high operating temperatures, power efficiency, and the power supply's reaction to low input voltage.  But because this site is dedicated more to overclocking, we'll check for voltage fluctuations in an overclocked environment.  After all, that is what overclockers generally care about.


To test the power supply, a digital multimeter was used.  For idle voltage readings, the system was left on the desktop not running any programs.  For full load, the system ran 2 instances of CPU Burn-in, Prime95 torture test for maximum power consumption, PCMark2004 hard drive benchmark, and the Nature test in 3DMark2001SE.  CPU Burn-in is a good program to maximize the CPU load.  The SilverStone ST65ZF was pretty much rock stable throughout all tests!  I was amazingly shocked by such great results.



Conclusion and Thoughts

SilverStone has released a monstrous power supply and has really impressed me with what they are capable of.  I used to just look at SilverStone as a chassis provider, but after using the ST65ZF, my point of view has certainly changed.  The fully packed ST65ZF provides rock stable voltage rails under overclocked conditions and is capable of providing up to a high 650W of pure power.  Although the sacrifice for this high performing power supply is the noise level, it still does not make the PSU a bad choice.  To some, performance will always be the number one priority.  It all depends what you plan to use the power supply for.  I am more than pleased with my sample and have officially made it my new power supply for my testbed. 


  • Great performance
  • Provides 42A total to quad 12v rails
  • Well priced for a high performance PSU
  • Use of large heatsinks helps heat dissipation
  • Plenty of power connectors
  • Good efficiency at 75.8%


  • Loud, due to single 80mm fan

We would like to thank SilverStone for providing us the sample.  If you have any questions or comments, feel free to hit us up in the forums. You can also check out more of our latest reviews on the front page.