The ZM600-HP relies on a single fan to move air out of the case and through the power supply.  Now lets talk about some of the steps that Zalman has taken to insure that this power supply operates cool and without any issues.  The first thing they have done is to help reduce the Bridge Diode heat that is generated during the AC to DC conversion by using two bridge diodes instead of the cheaper and more heat producing single diode version.

The next step was to reduce the PFC Circuitry's Switching Field Effect Transistor heat  generation by the use of  3 Parallel switching Field Effect Transistors instead of the normal 1 or 2.

Something worth mentioning is Zalman's CNPS, this stands for (Computer Noise Prevention System) this refers to a system that can reduce a conventional computer' noise level by 30db or more to an inaudible level (20db or less).  Zalman’s silent/ultra-quiet components enable the realization of noiseless computers of the highest quality.  You can see that Zalman has a number of items that fall into this very quiet operating category, so if you are building HTPC these are a few items you may want to consider for you system.

You might just think the placard on the side of the power supply is only there to tell you how much power the power supply has, but if you look closer you can see the is more iformation you can use to learn more about your product.

The first sticker tells us the power supply supports active PFC, so what exactly is active PFC?  To start with you have to realize that there three types of PFC (Active - Passive - Non). The preferable type of PFC is Active Power Factor Correction (Active PFC) since it provides more efficient power frequency. Because Active PFC uses a circuit to correct power factor, Active PFC is able to generate a theoretical power factor of over 95%. Active Power Factor Correction also markedly diminishes total harmonics, automatically corrects for AC input voltage, and is capable of a full range of input voltage. Since Active PFC is the more complex method of Power Factor Correction, it is more expensive to produce an Active PFC power supply.

Next up we can see that the ZM600-HP has  a Ball bearing fan as opposed to a sleeve bearing therefore it should run longer and quieter.  The next tag "W/noise killer which refers to the Computer Noise Reduction System.   The final tag states the power supply has passed the "Hi-Pot" test, which basically is a test to check to insure that there is proper insulation from the Hi-voltage and ground so that one doesn't get fried touching the case of the power supply.  You can also see the 120mm fan with the chrome fan guard here and the Zalman decal placed on the hub of the fan.

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