Be quiet! is renowned for its dedication to excellence in the realm of PC components, specializing in products that emphasize silence and performance. The brand's product lineup is extensive, encompassing high-quality power supply units (PSUs), cases, and cooling solutions, including air and liquid coolers. Be quiet! is particularly renowned for trying to achieve whisper-quiet operation across all its products, making it a favorite among PC enthusiasts who prioritize a noiseless computing environment. The brand's portfolio reflects a dedication to meeting the diverse needs of tech aficionados and professionals, with an array of products that emphasize noise reduction and efficiency.

This review shines a spotlight on the Be quiet! Pure Power 12 M 650W PSU, a standout product in Be quiet!'s PSU collection that illustrates the company's attitude towards product design. The Pure Power 12 M series is designed to provide dependable performance and quiet operation, catering to users who demand a good balance of power efficiency and acoustics with reliability and value. This model, in particular, strives to offer a compelling blend of performance and quality, making it an attractive option for individuals seeking a PSU that aligns with the requirements of both entry-level and advanced PC builds.

Packaging and Bundle

The Pure Power 12 M 650W PSU arrived in an elegantly designed package, boasting a predominantly black color theme accentuated by an image of the PSU itself on the front. This sturdy cardboard packaging is enhanced with a nylon bag and foam inserts, offering exceptional protection for the unit during transit. Specifications and detailed insights into the PSU's performance are conveniently printed on the back of the box.

In line with Be quiet!'s streamlined approach, the package includes only the essentials for the PSU's setup and use. Unboxing reveals a selection of mounting screws and an AC power cable. Distinguishing itself with a fully modular configuration, the Pure Power 12 M 650W allows for the detachment of every DC power cable, including the 24-pin ATX connector. 

The cables are uniformly black, from the connectors to the wires, and primarily adopt a flat, ribbon-style design for ease of cable management, with the notable exceptions being the sleeved 24-pin ATX and the 12VHPWR cables, the latter specifically engineered to handle up to 450 Watts. Oddly enough, there are two CPU 12V connectors but one is limited to a 4P connector only.

The Be Quiet! Pure Power 12 M 650W PSU

External Appearance

The Be quiet! Pure Power 12 M 650W PSU is encased in a chassis that measures 86 mm × 150 mm × 160 mm (H × W × D), extending just slightly beyond the ATX standard specifications. This design ensures the PSU fits seamlessly into a broad array of modern PC cases, especially those tailored for high-performance components. Nonetheless, even though its dimensions are typical of high-performance products, it could be significantly shorter considering its cooling fan and power output.

Be quiet! has placed considerable emphasis on the external design of the Pure Power 12 M 650W, an odd choice for a product primarily aiming to compete in terms of value. The unit features a slightly textured black finish, with the company's logo subtly embossed on the right side of the chassis for a touch of elegance. The fan finger guard is a sleek, stand-alone parallel wire design. An informational sticker detailing the PSU's certifications and specifications is neatly placed on the left side, while the top remains unadorned.

At the rear, a standard on/off switch is located adjacent to the AC power receptacle, with a small decorative sticker next to them. The modular cable connectors occupy most of the unit’s front side, each marked with a clear white legend for easy identification. Notably, the Pure Power 12 M 650W includes a 12VHPWR connector, showcasing its compliance with the ATX 3.0 specification, making it one of the very few units that are ATX 3.0 compliant with such a low power output.

Internal Design

The Be quiet! Pure Power 12 M 650W PSU is equipped with a cooling fan of their own design and an unknown OEM to us, featuring an all-black design and a rifle bearing engine for durability and efficiency. The PSU's design allows for the inclusion of a larger fan, yet a 120 mm model has been selected to fit within the unit. This fan operates with a maximum speed of 1800 RPM, a fair maximum speed for an 120 mm fan placed in charge of cooling a 650W unit.

The Pure Power 12 M 650W PSU is manufactured by HEC/Compucase, an OEM known for producing power supply units across various segments of the market. While HEC/Compucase may not be as widely recognized among the top-tier PSU suppliers, it is one of the oldest and most experienced companies in the field of PC power supplies, with their reputation for quality and reliability standing firm within the industry.

The design of the Pure Power 12 M 650W employs established, reliable topologies, reflecting a focus on delivering value and dependability. The PSU's filtering stage, located at the entry point of the AC receptacle, includes three Y capacitors, two X capacitors, and two large filtering inductors, followed by a rectifying bridge attached to its dedicated heatsink. The Active Power Factor Correction (APFC) components are placed on a significant heatsink across the edge of the PCB, featuring two APFC MOSFETs (Infineon 6R190P6) and one diode, alongside an encased filtering inductor and two Teapo capacitors (430 μF each).

For the primary stage, the PSU employs a half-bridge LLC topology placed on a large dedicated heatsink, a highly typical configuration in modern mid-range PSUs. On the secondary side, four Onsemi 5C430N transistors on a vertical daughterboard are responsible for generating the 12V line, while the 3.3V and 5V lines are produced through DC-to-DC conversion circuits on another daughterboard. This modular approach to circuit design aids in maintaining a clean layout.

The secondary side capacitors, a combination of Teapo and Nippon Chemi-Con, offer a balance between cost-efficiency and reliability. This component selection reflects a strategic approach to maintaining high-quality standards while also considering production costs.

Cold Test Results (~25°C Ambient Temperature)

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

The Be quiet! Pure Power 12 M 650W adheres to the 80Plus Gold certification criteria, demonstrating commendable electrical conversion efficiency. Specifically, when supplied with a 115 VAC input, the unit exhibits an average nominal load range efficiency (spanning from 20% to 100% of its capacity) of 90.7%, and 92% when powered by a 230 VAC source. The peak efficiency of the unit takes place at 50% load and is at 93.4% or 92.6% for an input voltage of 230 VAC or 115 VAC respectively. These figures align well with expectations for a product within its efficiency class.

The Be quiet! Pure Power 12 M 650W PSU does not feature a "hybrid" fan mode, resulting in the fan being operational from the moment the power supply is activated. However, due to its design, the fan maintains a low speed for up to 60% of the load capacity, which helps in keeping the unit operating quietly, especially under standard conditions at room temperature. As the load surpasses approximately 400 Watts, the fan's speed increases significantly to address the increased thermal output of the PSU. The internal temperatures of the unit remains low at all times, with the thermal control circuit being particularly aggressive when the load is greater than 500 Watts.

Hot Test Results (~45°C Ambient)

The Be quiet! Pure Power 12 M 650W PSU experiences a slight efficiency reduction under elevated ambient temperatures, as observed during its hot testing phase. Despite this, the unit maintains commendable performance levels, even when operating at maximum capacity. The marginal efficiency drop across its operational range, especially at peak loads, serves to illustrate the PSU's adeptness at managing heat dissipation under arduous conditions while underscoring the reliability of its internal components against high temperatures. It is particularly interesting that Be quiet! specifies that the maximum operating ambient temperature for this unit is just 40 °C, yet it performed admirably well despite the greater ambient temperature.

The Be quiet! Pure Power 12 M 650W PSU's fan speed is engineered to scale linearly with the load, reaching maximum velocity only when the unit is operating at full capacity. This strategic fan control, coupled with the PSU's sizable heatsinks and efficiency that exceeds the average for its class, contributes to its excellent thermal performance. Even as the load escalates, the system's acoustics are managed effectively, ensuring optimal cooling efficiency in balance with acoustics throughout the unit's operational range. The PSU is not quiet under these operating conditions but the noise levels are tolerable up to half load, which is pleasantly unexpected for a unit operating at an ambient temperature higher than its rated maximum.

Despite the fan reaching high speeds under the guidance of the thermal control system, the Be quiet! Pure Power 12 M 650W PSU effectively manages its thermal output, maintaining internal temperatures that are relatively low for its class. When operating under loads above 90%, where the fan operates at its maximum speed, the PSU still keeps the temperatures below critical levels, well away from triggering the over-temperature protection (OTP) mechanism.

Power Supply Quality

The electrical performance of the Be quiet! Pure Power 12 M 650W PSU is laudable within its category, offering a competitive edge in its segment. Voltage regulation is impressively tight, with the 12V rail demonstrating around 1% variance, and even better performance observed on the 3.3V and 5V rails, underscoring the PSU's meticulous attention to maintaining stability across all outputs. This precision is particularly notable, considering the tendency of some manufacturers to prioritize the 12V rail over the secondary rails. The ripple suppression is exemplary, with maximum values reaching 32 mV on the 12V line, 20 mV on the 5V line, and 18 mV on the 3.3V line, illustrating the PSU's ability to deliver clean power under varying loads.

During our routine evaluation, we examine the fundamental protection features of all power supply units we review, including Over Current Protection (OCP), Over Voltage Protection (OVP), Over Power Protection (OPP), and Short Circuit Protection (SCP). The Be quiet! Pure Power 12 M 650W PSU met all standard protection tests, affirming its capability to respond effectively in situations that could compromise the unit or its connected hardware. It demonstrated sharply tuned Over Current Protection (OCP) for the 3.3V and 5V rails, activating at 114% and 116% of their maximum currents, respectively. The OCP trigger point of the 12V rail is slightly higher, at 122%, but that remains a very sharp figure for an ATX 3.0 PSU. This sensitivity level ensures a reliable safeguard while maintaining a balanced performance across different loads.

Particularly noteworthy is the Over Power Protection (OPP) feature, which allows the PSU to manage output levels up to 112% of its nominal capacity before shutting down. This capacity to handle momentarily higher outputs without immediate shutdown offers a buffer against sudden spikes in demand, though it is designed to operate safely within its rated specifications, thereby ensuring longevity and stability even under considerable stress.

Conclusion

In the landscape of power supply units, the Be quiet! Pure Power 12 M 650W PSU stands out as a noteworthy contender, particularly for those wanting to balance overall performance, quality, and cost. Be quiet!'s approach with the Pure Power 12 M 650W leans towards dependability and time-tested designs, opting for reliability and consistent performance over chancy innovation.  This strategy, although it bodes well regarding the PSU's reliability, might pose questions about its edge in a market driven by continuous innovation.

The construction and electrical output of the PSU are commendably solid for a product of this class. HEC/Compucase is the veteran OEM behind this design, a company known for their competence in the mid-range market and possibly the reason behind the lengthy 10-year warranty. Choosing a 120 mm fan for cooling, despite its high quality, hints at a compromise between cost and the potential for superior cooling with a larger fan, with the slightly larger-than-usual heatsinks being the saving grace of this design. Electrical characteristics, including stable voltage regulation and effective ripple control, meet the expectations set by its 80Plus Gold rating without pushing beyond these benchmarks, indicating a product that performs reliably within its design parameters but does not surpass them.

Thermal management and noise performance offer a nuanced picture. The PSU maintains quiet operation under normal use; however, challenges arise with increased load or temperature, where its acoustics performance greatly deteriorates. Nevertheless, its efficiency and electrical integrity are very slightly impacted by the elevated ambient temperatures, which is quite a feat considering the very low ambient temperature operation threshold set by the company. From a technical point of view, the designer opted to lean towards low operating temperatures and ensure the PSU’s long term reliability rather than allow the unit to run quieter but hotter. This design choice is certainly reasonable and yet, at the same time, places a small dent on the Be quiet’s ethos of striving to design the quietest products possible.

The greatest drawback of the Pure Power 12 M 650W PSU is its retail price. At $99, the price tag of the 650W 80Plus Gold unit will raise eyebrows, particularly among budget-conscious builders or those comparing options within a highly competitive market. While the price point is on the higher side for a 650W PSU, it's important to consider the value added by the unit's 10-year warranty and ATX 3.0 compliance/capabilities. These offer peace of mind and a sense of security in the long-term reliability of the product, which can justify the initial investment.

Ultimately, then, the Pure Power 12 M 650W is trying to straddle a very fine line with regards to quality and performance. Paying a premium for a Gold-tier power supply simply isn't going to appeal to most budget-minded builders, but for enthusiasts and professionals who value the combination of balanced performance, modularity, and reliability – underscored by a generous warranty – the investment can be seen as reasonable. The assurance of compatibility with the latest and future hardware further adds to its appeal, suggesting that the Pure Power 12 M 650W PSU is not just a purchase but an investment in a system's long-term viability.