Be Quiet! Straight Power 700W Power Supply Review

Be Quiet! has one of the strangest, if not the strangest, brand name in the computer technology industry. Their name however is very well known as well, as they are the most popular European manufacturer of computer power supply units. They have a very strong presence in Europe and the company is now exporting their products to Asian and North American markets as well. Be Quiet! is particularly well-known for designing their products with low noise operation in mind. Today we will have a look at their mainstream PSU series, the Straight Power 10. There are eight units in the series, four of which are modular. The second most powerful modular model, the Straight Power 10 CM 700W unit found its way into our labs. We will see how well it performs in this review.

Specifications and features (summary, as provided by the manufacturer)

• Virtually inaudible operation achieved through a broad array of meticulous optimizations, including the use of a be quiet! SilentWings® 3 135mm fan
• SilentWings® 3 fan features an advanced fan frame, an airflow-optimized fan blade, fluid-dynamic bearing with copper core and a high-quality 6-pole motor for less vibration
• The funnel-shaped fan opening of the PSU case is significant big and allows high airflow intake
• 700 Watts of continuous power with stable four 12V-rail design
• 80PLUS® Gold certification and up to 93% power conversion efficiency
• Sleeved cable lengths for improved cooling and more attractive appearance
• NVIDIA SLI Ready and AMD CrossFireX certifications allow you to build powerful Multi-GPU systems with confidence
• Product conception, design and quality control in Germany

Packaging and accessories

Be Quiet! supplies the Straight Power 10 CM in a simple, medium sized box with a very serious appearance. The main theme on the dark packaging is a picture of the unit itself, with the series name boldly printed beneath it. Inside the box, we found the common power cable, five black screws (why five instead of four?), a few cable ties, a manual, and two bundles of modular cables. Each modular cable bundle is held together with a reusable cable strap.

The Be Quiet! Straight Power 10 CM 700W offers the following number of connectors:

The Power Supply

The Be Quiet! Straight Power 10 CM certainly is visually different from the majority of computer PSUs. As with most Be Quiet! PSU products, the fan cover has been replaced with a parallel grid wire guard. Other than that, the satin black body that this unit is using is a typical ATX steel chassis, with the company logo embossed on the right side of the unit. On the left side of the body, the company placed the sticker with the electrical specifications of the power supply.

The “CM” designation stands for “cable management”, meaning that this unit is of modular design and that its cables are removable – with the exception of the ATX 24 pin connector, which is hardwired to the main body. The front side is perforated, as with all modern PSUs, for the warm air to exit the unit to the outside of the case. With this unit however some of the air will also escape from the partially perforated rear side of the chassis as well, to the interior of the case.

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Perhaps the most notable feature of this PSU is the presence of the SilentWings fan, which are Be Quiet!’s pride and joy. The 700W version features a 13525-HF fan, which is a 135mm fan with fluid dynamic bearing and a maximum speed of 1800RPM.

Fortron-Source (FSP) is the designer behind the Straight Power 10. Their 80Plus Gold certified platform is a complex primary side with an Active Clamp Reset Forward (ACRF) topology and synchronous rectification on the secondary side. The filtering is acceptable, with 4 Y capacitors, 2 X capacitors and 2 coils. There is a single input bridge on a dedicated heatsink. All of the capacitors, including the main 390μF capacitor, are supplied by Teapo, with the sole exception of a single capacitor that filters the 5VSB line which comes from Nippon Chemi-Con. Teapo is a Taiwanese company which is not terribly popular amongst enthusiasts. We have to say however that the quality of Teapo capacitors has improved vastly over the past decade.

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Testing and results

For the testing of power supply units, we are using specialized equipment, details of which may be found in this article: Power Supply Testing Equipment & Methodology. At this point, we should also stress that opening a power supply not only voids your warranty, but also is very dangerous. Even if the power supply is not connected to an AC outlet, the capacitors of modern PSUs can easily store enough energy to kill any adult. There are no serviceable components inside a power supply and one can gain nothing by opening it, so just do not do it.

The Be Quiet! Straight Power 10 CM 700W PSU displayed good performance during our testing. The voltage regulation of just 1.4% on the 12V line and 1.2% on the 3.3V/5V lines is exceptional. On the other hand, the ripple filtering is good but unimpressive by today’s standards. A maximum ripple of 48mV is less than half of the 120mV design limit, but it could have been lower considering the price range of the unit. FSP however, rarely focuses on very strong voltage ripple filtering on their designs.

The efficiency of the Straight Power 10 700W unit meets the 88%/92%/88% 80Plus Gold requirements at 20%/50%/100% load respectively. The maximum efficiency reached 92.4% at 50% load, a very good result for a mainstream unit. It holds very good efficiency levels at high loads, with a minimum of 89.7% at maximum load. On the other hand, the efficiency drops fast at very low loads – at 20% load the efficiency drops to 88.3%, which meets the 80Plus Gold levels, but is much lower than the average efficiency of 90.7% that this unit has.

Be Quiet!’s Silent Wings fan seems to be working wonders at low loads, but there is only so much it can do once the unit is under stress and there is a lot of heat generated inside. As such, the Straight Power 10 CM 700W unit is entirely silent with a load up to 350 watts, but it will become clearly audible from 1m away once the load reaches 450W. At maximum load, the noise level reaches over 43dB, a figure we consider uncomfortable for daily use.

The operating temperature of the Straight Power 10 CM 700W is fairly low, which was to be expected from an 80Plus Gold certified unit with this level of power output. As it starts to get warm, at 50-60% output, the fan speeds up and maintains low operational temperatures; at the expense of acoustics performance, unfortunately.

Final Words and Conclusion

Be Quiet! markets the Straight Power 10 series as their mainstream offering, with the series being a stepping stone between the value Pure Power series and the premium (and ludicrously expensive) Dark Power Pro series. With models ranging from 400W to 800W and modular designs available, the Straight Power 10 series addresses the needs of the vast majority of advanced users.

The performance of the Straight Power 10 CM 700W unit that we reviewed here today is very good overall. It has excellent voltage regulation, efficiency that easily meets the 80Plus Gold standards and the unit operates quietly while not heavily loaded. It is aesthetically appealing and very well made as well. However, the voltage ripple filtering is good but unimpressive for the price range of this unit, as the thermal performance and build quality are as well.

The Straight Power 10 CM 700W unit currently retails for $109.90 including shipping. At first, the price seems fair for what this unit offers: good overall performance, 80Plus Gold efficiency and a modular design. It is however, in a market category where it will be facing tremendous competition. We can easily find 80Plus Gold certified modular units with about the same power output retailing for much less, or for about the same price but with only Japanese capacitors installed in them. The Straight Power 10 CM 700W is definitely not a bad choice, but we would have a hard time recommending it at its current retail price. Nevertheless, if the price drops in the near future or you can get a good deal somewhere, it will certainly not disappoint you as a product.

–Justicar