Power supplies are now coming into their own in the PC-build market with an increasingly large number of builders, including first-timers, recognizing the need for high-end, stable PSUs to drive their custom rigs. Concerns over PC noise have also begun to culminate in an ever-increasing market for tools and devices that will keep our rigs quiet.

The Be-Quiet company has, over the past few years, begun building a solid reputation across Europe for innovative products designed to keep computers cool and quiet. Anyone not familiar with the Be-Quiet brand will more than likely have heard of their sister companies Zalman and Cooler Master. These companies and others are all subsidiaries of German-based Listan International.

With so many reputable companies on the market, if Be-Quiet has any aspirations of moving into the North American arena, it's essential that they provide quality and value for our money. To see if they have what it takes, let's first start with a look at their feature list:

Features

• Quad (4) +12V Rails
• Support for ATX 12V v1.3 and ATX 12V v2.2
• Support for EPS 12V 2.91 (Dual-CPU / Server support)
• MTBF (operating life) of greater than 100,00 hour @ 40C
• Active PFC - 83% & 50% Load & 99% @ 100% Load
• Over Voltage Protection
• Over Current Protection
• Short Circuit Protection
• RoHS Compliancy
• 3 Year Warranty
  

  DC Output:	+3.3V	+5V	+12V1	+12V2	+12V3	+12V4	-12V	+5Vsb
  	32A	30A	18A	18A	18A	18A	0.5A	3A
  			41A
  	170W		492W				6W	15W
  	550W

For any enthusiast build and for many mid-range builders, multiple +12V rails are not a luxury, but a necessity. Multiple rails providing stable power to the system mean fewer fluctuations in voltage, which equates to cleaner power and more system stability. As we continue building machines that conatain a copious amount of GPUs, multiple CPU cores, and a plethora of hard drives; the need for an abundant amount of stable +12V power only increases. Be-Quiet's StraightPower series ships with a total of four +12V rails. Each of these rails can deliver up to 18A, with a combined amp limit of 41A. On a 550W power supply, we really want to see the collective +12V amps total in the high 30s. At 41A, the StraightPower 550 meets our expectations and provides us with a little headroom as well. The only downside is that none of the rails support above 18A. We would like to have seen at least one of the rails suport above 20A, just for future upgradeability.

CONTENTS AND CABLING

At first glance, the retail box dimensions and heft suggest that this PSU promises to be a real monster. Upon opening the box, however; we found the PSU to be a small footprint model with dimensions of 14cm(L) x 15cm(W) x 8.7cm(H). It's diminutive size allows for the flexibility to use this power supply in a variety of cases ranging from a small form factor (SFF) to a full tower model. The packaging of the PSU was top-notch, and appears to be well protected for shipping.

The power supply itself felt surprisingly light once we removed it from its packaging, with approximately half of the overall weight being attributed to the cables themselves. While the PSU was light, it still felt to be well constructed and solidly built.

We took a closer look at the cable strands to get a better idea of what the StraightPower 550 was providing us with. There is a reason to the heft of these cables as there is a veritable cornucopia of connectors on this PSU. The average cable length was just under 2 feet (60cm), and we had no problems while using this PSU in our full tower BTX/ATX case.

Connectors
One (1)	20+4 pin motherboard connector
One (1)	4+4 pin motherboard connector (all 8 pins are required for server boards and some multi-CPU boards.)
One (1)	3.5" Floppy Drive Connector
Two (2)	6 pin PCI Express Connectors
Six (6)	4 pin Molex connectors
Eight (8)	SATA connectors
Three (3)	Fan Connectors (each cable strand has a 4 pin Molex and 2 pin Speed control connector)

While most companies are shorting you on either molex or SATA connectors, we were estatic to see six (6) molex and eight (8) SATA connectors on this power supply.

Notice the sleeving, even between connectors on the same cable.� Many power supply manufacturers tend to neglect these areas.

In addition to peripheral molex and SATA connectors, Be-Quiet provides plenty of fan hookups too.

We were pleased to see cable sleeves on all of the cables save the 3 fan cables. Be-Quiet did a stellar job in their sleeving duties, providing a strong and durable sleeve, while allowing for the much needed flexibility to move and bend these cables inside of our case. And as mentioned, even the areas between connectors come sleeved.

We were happy to see that the StraightPower 550 comes with its own cable-management startup kit. Be-Quiet provides six (6) velcro wraps and six (6) zip ties with the PSU for cable management. We applaud Be-Quiet for this type of behavior as it not only shows thoughtfulness on the part of the manufacturer, but when used properly, these cable ties will allow for better airflow and a cooler overall system. We will point out, however; that with 14 cable strands coming off of this power supply, we would have preferred to see double the number of cable ties come with the PSU - yeah, we're picky like that!

The power supply attached to our case using four screws and Be-Quiet provids more than enough for the job. Ten (10) screws are provided in all and are composed of five (5) standard screws and five (5) thumbscrews.

Be-Quiet's present line of power supplies is currently only available through European channels. This might explain why we only received a European-fitted power cable. While we could not use the power cable that came with the PSU, it did appear to be of high quality and heavy-duty construction.

EXTERIOR AND COOLING

The exterior of the StraightPower 550 is coated in a black, mirror-like finish. According to Be-Quiet, this finish has been specially formulated to lower EM and EMC interference. This finish appears on the entire PSU casing, both inside and out. The StraightPower 550 is an auto-switching power supply, so we didn't have to worry about whether or not the PSU was set for 110V or 230V.

On the side, we see the typical specification sticker outlining how many amps are available on each rail, and the total wattage.

Cooling duties are handled by a Protechnic Electric "Noise Magic" 120mm fan. This bottom-mounted fan, which is slightly offset on the power supply, pulls air from the case and blows it through the power supply and out the honeycomb mesh back. The PSU internals are installed on a raised-platform inside the case to allow for better airflow. At idle and 50% load the fan was virtually silent, even when we had our ear up to the case. Better yet, at 100% load, the fan never rose above a whisper.

The StraightPower 550 comes with a feature known as "Thermal Control", where in you can connect up to three case fans using the included fan speed connectors. Once attached via these connectors, the fan speed of the PSU fan and three case fans are controlled by the power supply itself using the internal PSU thermal sensor. During testing, we connected two of our case fans to the "Thermal Control" connectors and found it to work flawlessly. We saw no change in our case, CPU, or GPU temps and found that the computer did indeed run quieter.

INTERNALS AND TESTING

After feeling how light the StraightPower 550 was, we decided to crack open the case in order to see what kinds of parts were used in its construction. While we are happy to void our warranties in order to provide you with the most complete review possible, remember that removing the case will void your warranty. Furthermore; it is possible to receive an injury from electrical shock, even even when unplugged. So remember, don't try this at home. We're what you'd call professionals (Ed Note: Professionals, or dare-devil reviewers? - Paul Lilly)

The internal layout is extremely clean. High-quality components abound and can be seen throughout the power supply. Be-Quiet states that they use an optimized circuit board layout in order to promote better cooling and performance.

While we would have preferred to see larger heatsinks installed on the PSU, the installed heatsinks seem to work extremely well. Even after running at 100% load for more than 24 hours, the power supply was cool to the touch and voltages were dead-on stable.

In order to test the PSU, we installed it into a full tower case which housed the following components:

CPU	AMD 64 X2 4600+ - 2400MHz @ 1.4V
Motherboard	Asus A8N32 SLI Delux motherboard
Memory	2GB Crucial Ballistix PC4000 DDR RAM
Graphics	Two (2) BFG nVidia 7800GT OC 256MB (SLI)
Hard Drives	Two (2) Western Digital 74GB Raptor HDDs (SATA RAID 0) Two (2) Seagate 160GB HDDs (SATA) One (1) Seagate 160GB HDDs (SATA) One (1) Seagate 400GB HDD (IDE)
Cooling	Zalman CNPS9500 CPU Cooler Two (2) 120mm Antec High Performance Case Fans Two (2) 80mm Antec High Performance Case Fans
Optical Devices	Two (2) NEC 3550A 16X DVD Burners

To ensure proper testing, we used a digital multimeter to record all voltages. We tested every possible connection on the +3.3V, +5V, and all four +12V rails. These connections were tested under the following conditions:

• Computer at idle
• Playing a full-length DVD movie
• Running 3DMark 2003 tests
• Running at 100% load for 24 hours using Prime95

Throughout the tests, we performed large file copies (in excess of 60GB) in the background in an effort to max power output to all six hard drives.

As we mentioned earlier, every connector was tested to ensure consistent voltages across all rails and cable strands. In every single test, the voltages were identical across every connector and cable strand. When running testing applications like 3DMark 2003, its not uncommon to see a light ping-pong fluctuations in the voltages on the multimeter due to the nature of how these types of programs run. We encountered absolutely zero voltage fluctuation during our tests. Be-Quiet has produced an extremely stable and solid performer with the StraightPower 550.

Segment	Score	Comments
Feature-Set	10/10	550W of Power Four +12V Rails Active PFC Thermal Control of PSU & up to 3 Case Fans
Cables & Connections	16/20	Long Cables A cornucopia of connectors Fantastic cable sleeving does not hurt flexibility of cables Cable management ties included (Though we'd prefer double the amount) No North American power cable
Power	18/20	550W of Power Incredibly stable during testing Four +12V Rails providing 18A each or a total of 41A None of the rails support above 18A, which could potentially limit future expandability.
Performance	20/20	It handled everything that we could throw at it. 6 HDDs, 2 Graphics cards, and an X2 4600 - Need we say more?
Cooling & Noise	10/10	Virtually silent when running at idle or 50% load. Whisper quiet when running at 100% load. Thermal Control worked flawlessly with 2 case fans.
Warranty & Support	6/10	Received a response within 72 hours concerning a power cable replacement, but as of print there was no resolution to the issue.
Price / Value	7/10	As Be-Quiet is currently only available in the European market, no US/CAD price could be found. They are considered a good value/inexpensive in Europe.

Our Recommendation

The Be-Quiet StraightPower 550W power supply is by all accounts an excellent PSU. It easily handled everything we threw at it, but the lack of any +12V rails above 20A could inhibit its future expandability. Provided that they open up in the North American market, this is one of the better 550W PSUs we've personally tested.� If you are looking for quiet operation and stable power then the StraightPower 550W power supply from Be-Quiet is an excellent choice.