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Power Supplies Get Smarter
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1. Power Supplies Get Smarter

Given the popularity of our previous power supply articles (Strong Showing: High-Performance Power Supply Units and Really Cool and Quiet Power Supplies? ), we now look at four units with purported value adds besides low noise levels.

The Power One power supply from Sky Hawk features a unique function, which goes by the name of Audio Standby. The three other power supplies from Coolermaster, Thermaltake and Sirtec display the power output in real time. Read on to find out which devices offer features that you might really want - and use - in a power supply unit.

2. Skyhawk Power One
General Impression

The Power One GM620SA

Skyhawk's ATX12V 2.01 Power One unit offers what the vendor calls Audio Standby, which is supposed to allow you to listen to music even when the computer is switched off. We tested a pre-production version of the 600 Watt GM620SA.


The Skyhawk's Power Supply Components

An unusual feature of the power supply is the accessories. An IDE cable is not usually included in the power supply package, and an audio cable for the analog connection to the CD-ROM drive is also available. In addition to these components is a 5.25" Molex connector, which provides voltages of 5 and 12 Volt even when the computer is switched off.

3. Skyhawk Power One, Continued

An IDE cable and slot plate with a jack receptacle represent unusual power supply accessories.

The audio cable is a switch between the CD drive, motherboard and jack receptacle.

The way the Audio Standby feature works is very simple. You insert an audio CD into the CD-ROM drive. After pressing the drive's play button, the CD is played back via headphones or speakers connected to the slot plate. But what is in fact a good idea does, however, have a few catches.

First, the CD drive requires a play button. This type of button has now, however, become rare- we found very few drives in our lab that had a play button. Secondly, it can only be used for merely playing back the CD, as this solution does not allow tracks to be skipped or repeated.

Regarding the slot plate, why should the user plug in his or her headphones at the back of the computer, when the CD drive already offers a headphones connection? For ordinary loudspeakers, the slot plate may appear useful, but even here the user would be required to change the plugs around to play back normal sound. No one crawls behind the computer a number of times each day to do this.

The fact that 12 and 5 Volts of power are also available when the computer is off opens up entirely different options. Which user hasn't wished there was a light inside the tower when fitting new components inside the computer. While many case modders do have colorful lights with interesting effects inside the case, these are however switched off when work is to be performed on the computer. With Skyhawk's power supply, it is also possible to operate lights such as these when the computer is off. This can prove far more useful than the Audio Standby function.

4. Cables And Connectors

The power supply features cables that can be attached for the devices. The only components that are permanently connected to the power supply are the ATX cable, the P4 connector (also available in an 8-pin version for a multi-processor system) and a 5.25" Molex connector for the Audio Standby function. The ATX connector is available as a 24-pin version, which can be split, allowing it to be used without an adapter on older motherboards.

A Simple connection thanks to the jacks.

All cables are included in the package.

Five jacks on the rear of the power supply are used for connecting cables that are truly necessary. This helps to keep things nice and tidy inside the case. The following cables are available to choose from:

  • One cable with PCIe connector for graphic cards
  • One cable with three 5.25" Molex connectors
  • Two cables with one floppy connection each and two 5.25" Molex connectors
  • One cable with two SATA connectors

A sufficient number of connectors are provided, although there should have been two extra SATA connectors. All the same, thanks to the modularity, the option is available to subsequently replace two 5.25" connectors with SATA connectors.

A word of caution regarding the PCIe connector: Even if the connector fits in the opposite jacks - the black one must be plugged into the power supply, and the transparent one into the graphics card. Swapping sides around results in a short circuit due to the different configuration.

All voltages are accommodated.
5. Power

Switching on the power supply for the first time can be a baffling experience. First, a mysterious blue light is emitted from the inside the device, but no fans rotate. However, once the device has had the chance to warm up, the fans slowly start to rotate and the world is back to normal again.

This device passed the set of benchmark tests without any problems whatsoever. All the voltages are within the tolerances at all times, and it delivers the maximum power of 600 Watt without any difficulties.

Although all the information is available, the layout could be clearer.

In all the measurements taken, the efficiency is within the 75% range, which, consequently, is very good. Only in standby mode is the efficiency very low, with an entire 13 Watts being drawn at the lowest load, and an impressive 28 Watts at a high load. Presumably, the additional switching regulator supplies the 12 Volt rail.

The power unit's price tag at $100 (€90) is also more than just reasonable.

6. Coolermaster RealPower 550 W
Overall Impression

The 550 Watt version

With its RealPower 550 W, Coolermaster has produced a more powerful power supply compared to its previous offerings. The equipment is the same as that of the 450 Watt version . This power supply also conforms to the ATX12V 2.01 standard. The old version of the RealPower power supply also featured a power meter. A major point of criticism regarding this device was that the display was very hard to read. Disappointingly, Coolermaster has made very few changes to the display. So what is new about this unit?

Silver or black? Coolermaster allows the user to choose.

The new features include two cover plates (black and silver) so that the display matches the case better. However, the reading indicated by the needle is hardly visible, which makes this feature devoid of much practical use.

In daylight, it is still possible to read the needle - that's if you're close enough to it...

...in the dark, however, it is only possible to guess the position of the needle.
7. Cables And Connectors

The ATX connector has a 24-pin configuration. The connector can not, however, be split, meaning that for older boards it is still necessary to use the supplied adapter. A new feature is the PCIe connector used for connecting to graphics cards. Caution should be exercised here, as the power supply also comes with an EPS connector. Although this mechanically fits onto the graphics card, the configuration of the cables is however entirely different, with the destruction of the graphics card being the outcome in the worst case scenario of mixing up the connectors. The instructions explain the meaning of the color coding of the connectors.

A word of caution: On the left, the PCIe connector; on the right, the mechanically identical EPS connector

The number of SATA connectors has been upped to three - which is pleasing. In addition, six 5.25" Molex connectors and one floppy connector are available. Users of dual processor systems have also been taken into account. The P4 connector is also available as an eight-pin version. As such, the power supply is also suitable for workstation systems.

The full range from 90 to 260 Volt is covered.
Power

Like its predecessor, the 550 Watt version has no problems whatsoever in terms of voltage stability. At a 550 Watt load, the automatically controlled fan does, however, rotate very powerfully, creating a disturbing effect.

All the details there and nice and neat - the way a nameplate should be.

Coolermaster has boosted efficiency significantly. Both under full and under half load the device works with a level of efficiency of over 79%, placing it at the top of the test field in terms of efficiency. Even an efficiency of 75% under a low load is quite respectable.

In standby mode, the device is on a par with its predecessor, with just under 4 Watt being drawn from the mains at a low load and 19 Watt at a high load.

We currently have no details on the price for the 550 Watt version.

8. Thermaltake PurePower TWV 500W
Overall Impression

The TWV500 from Thermaltake

Thermaltake, commonly known for its coolers, has come up with something very special. The ATX 12V 2.01 power supply TWV 500 incorporates a digital power meter in addition to a fan controller. By means of a 5.25" front panel, it is possible to control the speed of the power supply fan and that of an enclosed additional 4.72" (120 mm) fan.


The power supply's components: on the right, the additional 4.72" (120 mm) fan.

The power meter and both setting potentiometers.

Well concealed (left) - the connection for the potentiometer at the fan.

Not much inside: Two potentiometers and the seven segment display.

The fan is supplied with power via a conventional 5.25" Molex connector. To control the speed, an additional jack is available, which is connected with a setting controller from the front panel. The same kind of cable is also used to connect the fan from the power supply. And a third cable is used to display the power reading.

On the left, the tacho signal, in the center the potentiometer connection for the fan, on the right, the readout for the power meter.

The manufacturer could have at least combined the last two cables, thus avoiding the spaghetti wire syndrome. The user should connect the panel to the power supply even if he or she does not wish to use the manual control. If the cable is not connected, the fan rotates at full speed and the power supply becomes incredibly loud.

9. Cables And Connectors

Thermaltake also opts for "modularized cable management," meaning that it is only necessary to connect those cables the user actually needs.

All the cables at a glance.

It is also possible to disconnect the ATX cable. Although it is also needed, it can however be removed for a short while so that it no longer gets in the way, as it usually does, when working on the computer.

A large number of cables are available:

  • Two cables each with two SATA connectors
  • Two cables each with one PCIe connector (SLi)
  • One cable with a four-pin P4 connector
  • Two cables with one floppy connector and three 5.25" Molex connectors
  • One cable with three 5.25" Molex connectors

These connections ensure that ample reserves are available for the future. The picture is spoilt slightly by the ATX connector. Although this is a 24-pin version and one that can be split, it is not possible to clip the four extra pins onto the large connector. This means that these four pins are not secure and can, in some cases, slip out of the motherboard.

Although it can be split, it is not secure: The four additional pins can come loose.
10. Power

The power supply from Thermaltake is compatible with 115 Volt and 230 Volt

No faults can be found as far as the power output is concerned. The device is capable of delivering the specified 500 Watt without any problems, and all the voltages are within the tolerances. One thing that is completely inaccurate, however, is the power readout.

Although we set the unit at exactly 400 Watts on the test platform, the display jumps back and forth between 350 and 385 Watts, while the occasional short surge down to 300 Watt is also indicated. Consequently, the display is intended more in the way of an estimate than as a measurement.

The Thermaltake digital display is easy to read.


All the information is available and clearly laid out - just as it ought to be.

All the same - and this is where the display can score points compared with the Coolermaster display - it is easy to read from virtually any angle both by day and by night.

The device delivers an efficiency of 75% at half and 74% at full load, which is very respectable. At a low load, the efficiency is less at 69%, which ought to be higher.

In standby mode, 9 Watts at a low load and 18 Watts at a high load is drawn from the mains, for which this power supply is marked down. All the same, the rates are all right. What is more, the power meter remains at 10 Watts, irrespective of which load is set.

The price of $130 (€110) is reasonable for the scope of functions available.

11. Sirtec's Power Watcher
Overall Impression

Sirtec's voltage converter

The Power Watcher PW-480-302-DF from Sirtec supposedly delivers 480 Watts, with 550 Watts being specified as the peak load. As the name "Power Watcher" suggests, the power currently consumed is also displayed by this power supply. Sirtec has opted for a digital power meter with a seven-segment LED display, which is very easy to read, both in daylight and also in the dark.

The power consumption is displayed on a 5.25" screen.

Not a great deal of technology is required.

This device is an ATX 12V 2.0 power supply. While the ATX connector has only a 20 pin configuration, the adapter extends the cables to 24 pins. As to whether this makes sense or not is doubtful.

Cables And Connectors

The box lists the "Smart Cable Management" feature. This does not refer to the cables that can be connected to the power supply, however, but merely their sheathing.

Connection for the power meter (left) and tacho signal (right).

No fewer than nine 5.25" Molex connectors are available, these being split into three looms. Two looms also feature a floppy connector as well. Only two SATA connectors are available, which could prove a little too tight for the future. In addition to the 20 pin ATX connector (with adapter to 24 pins), the obligatory P4 connector is also supplied.

12. Power

Neither was the Power Watcher thrown by the benchmark marathon. The device can deliver the required 480 Watts without any problems, and the voltage fluctuations never go beyond the tolerances defined by the ATX specification. The maximum current of 18 A on the 12 Volt rail is a little on the weak side, particularly for the latest Pentium 4 processors featuring the Prescott core and power-hungry graphics cards. These devices require 12 Volts, and can present bottlenecks with this power supply. If the current is exceeded by only a minimal amount, the power supply switches off. For this power range, other manufacturers offer considerably higher currents on the 12 Volt rail.

Details on the power most definitively belong on this nameplate.

The efficiency of the device at full load is around 76%, which is a respectable value. At half load, this drops to 75%, at a low load it drops even further to a meager 69%.

With 10 Watts being drawn in standby mode at a low load and 19 Watts at a high load, this power supply is placed in the middle of the field.

The power meter in operation.

The power meter displays realistic values, even if these are slightly below the power output of the power supply. In standby mode, the display remains strictly at 2 Watts, as the actual consumption is not measured in this mode.

We currently have no details on the price for the Power Watcher.

13. Benchmarks

The measurements were performed with the THG power supply test platform. We have already presented this test platform in More power: The new power supply standard ATX 12V 2.0 , in which we also explain our testing methodology.

For the sake of a better comparison, we have also included the power supplies we previously tested from Strong Showing: High-Performance Power Supply Units in the new charts.

Efficiency Benchmarks

14. Efficiency In Standby Mode

Conclusion

Anyone who wishes to keep an eye on the current power consumption should not opt for the Coolermaster RealPower 550W, as it is virtually impossible to see anything on the small display with its minute needle, especially in the dark. Instead, it is far more advisable for users to opt for the Power Watcher from Sirtec. The LED display is easy to read from any angle. The PurePower power supply from Thermaltake is equally good in terms of the legibility of the display. However, due to the large jumps the power supply makes, the power measurement tends to instead offer more of an estimate than an exact reading.

The Audio Standby function of Skyhawk's Power One power represents a clever concept, but unfortunately offers no practical benefits for most users. One nifty, yet not-so-practical feature, is the possibility to set the power supply unit's voltage at 12 and 5 Volts, which can be used to only light up the PCs lights without turning the computer on.

Anyone looking for a truly efficient power supply, will opt however for the Coolermaster Realpower 550W , which constantly comes out at the top in our tests.