Specs, setup, notes
The formal specifications from Zalman's 'site.
System setup
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Intel Pentium 4 3.0GHz (15x200) Northwood CPU
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Zalman Cu7000 HSF
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ABIT BH7 i845PE motherboard
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512MB (2 x 256MB) Corsair XMS3500 RAM
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ATi Radeon 9800 Pro graphics card
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61GB IBM 120GXP Hard Drive
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Zalman ZM400A-APF Noiseless PSU
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PCToys PM-420A PSU
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Samcheer 420w PSU
Notes
Zalman pride themselves on the lack of noise exhibited by their products. The massive heatsinks and single fan combination should work well. A little chart highlighting the noise levels, courtesy of Zalman, is shown below.
The fan's noise output is dictated by the internal power sensor's temperature. Running idly, one has to put their ear next to the fan guard to ensure that the fan is actually functioning. There's very little air being drawn in. Raising the CPU's speed and voltage, and in turn raising the PSU's internal temperature a little, showed no discernable fan speed increase.
Artificially raising the PSU's internal temperature by running no case fans and a relatively weak CPU fan (68c CPU temp) still didn't cause the Zalman's fan to spin at anything other than a quiet whir. Other components, such as a Radeon 9800's fan, would mask its pitch, anyway.
Zalman quote a maximum 30dBA rating; that's still pretty quiet when considered in relation to other noise generated by PC components. Not quite a noiseless solution, it's the quietest PSU I've personally used. On to the voltage test.
