The be quiet! Pure Power 12 M 650W PSU Review: Solid Gold

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.

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.

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.

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.