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

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.