Skyhawk Power One Power Supply - Cooling and PFC

When it comes to cooling, the Skyhawk Power One doesn't break any new ground. It follows the typical packing of an 80mm fan as an exhaust on the back and a 90mm one on the bottom as an intake. It isn't heavy, as my ancient Enermax 430 is slightly denser in an unscientific comparison. The heatsinks inside aren't very large, especially given the power rating of the PSU. This model in particular is a "620W" one, though that rating is somewhat deceiving. Fifty of those watts come from the "audio standby" capability, which is only functioning when the computer is off. That brings it back to the similar 570W members of the Power One family in actual online output. 

The nice thing about this family is that they state that they comply with the latest specs, including features such as two 12V rails, each capable of 20A current. This is meant to deal better with all of the demand on that line by processors, and still provide power to motors and other 12V devices. The 5V rail is a substantial 50A, while the 3.3V one is rated for an ample 45A. These two lines had started to be less important in recent years, but have come back into fashion with the draw of high end graphics cards, as well as the recent revival of SLi and multiple GPUs. In order to remain future proof with respect to both dual/multi core processors, and the demand of these graphics cores, keeping available overhead on all power lines is actually something that matters. 

Unfortunately, stating that you comply and actually doing so are two different things. According to the Intel specifications for EPS 12V v2.1, the 2x2 4 pin connector should not share the same rail as the 12V rail going to the rest of the system, specifically stating that they should not be connected at any point anywhere in the PSU. The ATX12V v2.0.1 spec is more open, stating that the second 12V rail "be a separate current limited output." With that wording in mind, the PCB of the Skyhawk Power One more or less meets the function of ATX12V v2.0.1 because of its current and voltage demands, but does not do so for the server oriented EPS 12V v2.1 requirements, due to its very clear wording. 

Is this ever going to affect your systems performance? Unlikely, unless you are running a high end Prescott or Nocona as well as another demanding 12V device, in which case overloading one circuit could affect the other due to them not being separately limited. Skyhawk is aware of this issue, and is working to correct it on new units.

One other feature of modern PSUs is something more for the companies that provide power to your house rather than for you. This is the "PFC" you hear about on many new units. The Power One comes with either passive or active PFC, depending on the model. For the one I'm testing today, they didn't make the distinction on what it carries. Since it is the top end model, I'm going to safely assume it makes use of active power factor correction. 

What does this do?  Basically, computer power supplies appear to the wall socket not as a toaster, or other similar resistive load. Instead, they are more like an inductive motor you'd see in a factory. As a result, the power company has to send more current than what you are actually paying for at the meter outside your house, which varies depending on how far out of phase the load is. One computer by itself isn't going to cause too much disruption, but imagine an office building with hundreds of computers, or a university campus with thousands!  Pretty soon all of those little loads added up become a large load. 

To prevent future issues with having to charge consumers based on their load factor as is done for industrial customers, most new PSUs carry some type of PFC to bring them back to looking like a simple toaster. Passive PFC is all that is really needed, and might even be the better solution for low load situations, as it does not eat any power itself to work. 

Active PFC, on the other hand, adds another small load internally to the unit. Of course, marketing being what it is, this is used as a "feature." To be safe though, I wouldn't advise getitng a PSU that didn't integrate any kind of PFC. The European Union has instituted requirements for all computers to have this feature; I don't see it being long before a similar law is created here in North America.

So how does this thing work?  Modular cables are great, so too are swanky looks, but they aren't worth much if the unit itself is next to useless. Luckily for Skyhawk, they were smart enough to realize this and ensure that this model doesn't fall completely into the "all style no substance" classification. Our test system is a fairly light overall load, but does have diverse requirements.  Let's see how the Skyhawk Power One fares.

Next: Testing >>
 

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