Silent PSUs (Silent PC Part 3) 5th July 2003
Today we'll be examining two of the quietest power supplies available. In the past quiet operation has come at a premium and by compromising in some areas. In this, the third article in our Quiet PC series, we'll see just how much things have changed in the last 6 months. The two products we will be examining are the Globalwin SAF 520W PSU with active PFC and case fan controller (hereafter referred to as SAF520W) and the Zalman ZM400A-APF (hereafter referred to as the ZM400A).
The UK distributor for Globalwin is Rainbow Components. Globalwin products have been renowned for their performance in the past and now the company is looking into formerly niche markets that have started to gain widespread recognition. Chief among these is the desire for a quieter PC and to this end Globalwin have released this new range of super quiet PSUs and a forthcoming mainstream (easy for the consumer to install) water cooling system.
Quiet PC have been around for a while now offering products exclusively aimed at silent PC operation. We have praised them in the past for their SilentDrive hard drive enclosures which have completely eliminated the whining of hard drives and no doubt saved some of us from high frequency hearing damage. While their silent PSUs in the past have been completely noiseless we have noted that they blow hardly any air and the maximum available was 300W - not enough for today's users. Now they have adopted Zalman's latest offering and a 400W PSU should be enough for the time being.
Here are the specifications of the two drives:
And for the ZM400A:
Both arewell specified. We received a Pyramid V Temperature Sensitive Fan Controller to go with the Zalman PSU and we'll take a look at that later along with the 80mm case fans Globalwin sent us that use a new ceramic bearing design, are transparent and rated at only 22db (our favorite quiet case fans, the PanaFlo ones, are rated at 26db by comparison).
The PSUs come in standard sized boxes which don't contain much details but are sturdy for transportation. The Globalwin box shows a diagram of how the two fans work in conjunction. The design doesn't allow for taking in air from above the CPU as some PSUs do but realistically that is not the job of a PSU and correct use of case fans should ensure a good airflow for the inside of a computer case.
Both units have plenty of Molex connectors so you're unlikely to need splitter cables
The use of a mirrored finish and gold finger guards adds a nice touch to the SAF520W. Also visible is the 3-speed setting for the fans which is easily accessible from behind the PC when installed.
The mirrored finish in all its glory although it won't really be appreciated without a transparent case or large side window. Incidentally, it threw the focus off on our camera so some of the pictures in this article are not of the highest quality. Taking the cover off the ZM400A shows a neat layout beneath with well soldered joints and large heatsinks.
The same is true of the SAF520W and also apparent is the design of the opposing fans. The components are laid out to maximize airflow. The ZM400A heatsinks from another angle show just how large they are. Powerful solenoids give an indication of the high quality components used.
Although the heatsinks on the SAF520W are smaller, the increased airflow from 2 fans makes up for this. Neat plastic panels can be seen on the ZM400A to prevent thermal dissipation through the outer casing and to direct airflow.
This is also true of the SAF520W and we would like more of these designs as they lessen to possibility of a short circuit.
The quality of construction of both PSUs is very good.
Included with the SAF520W is a lead which allows up to 3 fans to be run directly from the PSU which is very useful if you don't have enough motherboard headers or have high power fans such as Deltas and don't want to risk damaging the motherboard fan voltage regulators. The Velcro strips are for PSU case mounting rails. These are useful if there is a slight gap that they can fill and are also good for absorbing vibration. The fans are the latest ceramic bearing ones and almost completely silent, much quieter than our previous champions the PanaFlo fans and even quieter than our Papst fans. It seems these are the best case fans available from a silent operation point of view.
This is the pyramid fan controller. It automatically adjusts fan speed according to a built-in temperature sensor. The overall size is tiny and just shows how cumbersome similar solutions using a 5.25" bay are. The algorithm used is quite good unlike AOpen's automatic controller which seems to change speed every few seconds. The pyramid is much more subtle or uses very gradual adjustment - in either case it works well and more importantly without allowing the users to hear it adjusting fan speeds.
Testing showed that both PSUs coped without any problems with heavy loads even in a Dual Athlon rig. The ZM400A was completely silent but didn't blow much air out. This didn't seem to be a problem as the air wasn't very hot and in any case it was much better than Quiet PCs previous PSUs with which it was difficult to tell if any air was blowing. The SAF520 was also completely silent at the slow setting but a very faint hum could be heard at the high settings above the whoosh of air. It was not detectable from a normal seated position though.
In choosing a quiet PSU it should be noted that the PC will only be as quiet as the loudest component. There's no point having a quiet PSU if the CPU fan is a screamer. If the desire is to build a silent PC then either of the two products will serve admirably. If just upgrading a PSU then again it is worth getting a quiet PSU as both contenders performed very well as quality PSUs and the premium for quiet operation is small. More and more companies are waking up to the silent PC market and it looks set to be as big as the overclocking phenomena. These two products are setting standards for the future in this area and we don't hesitate to award them our Hardware Review Gold Accolade as the best in their class. If you need a beefy PSU then the SAF520W with its half a kilowatt can cope with anything including exotic forms of cooling. The ZM400A is also an excellent product backed up by Quiet PCs superb technical support and will make any purchaser happy.
We would like to thankRainbow Components and Quiet PC for providing us with the review samples.
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