The SeaSonic Focus GX-850 ATX 3.0 PSU Review: Cool, Quiet, and Robust

Hot Test Results (~45°C Ambient Temperature)

The SeaSonic Focus GX-850 has its output specified for an ambient temperature of 50°C. Generally, PC power supply units (PSUs) are categorized based on their temperature ratings, with 40°C typically associated with low-end to entry-level mainstream units, and 50°C designated for quality mid-tier to high-performance products. The 50°C rating of the SeaSonic Focus GX-850 is unsurprising considering its target market and class, and a welcome upgrade over the previous Focus Plus series, which was rated at 40°C.

The performance of PC power supply units (PSUs) tends to diminish as the ambient temperature increases, with the extent of the degradation largely influenced by the design and quality of the unit in question. In the case of the SeaSonic Focus GX-850, the energy conversion efficiency experiences a marginal drop of just 0.4%, a figure that stands out favorably, especially for a quality 80Plus Gold unit. This minor decrement is consistent across the entire load spectrum, exhibiting no notable variance even under substantial load conditions. Such outcomes imply that the thermal stress exerted on the active components is remarkably low to mild, showcasing the design robustness of the SeaSonic Focus GX-850.

In contrast to some models, the fan within the SeaSonic Focus GX-850 initiates almost immediately upon powering on when the ambient temperature is high, reflecting a proactive approach to thermal management. The fan's operation progressively escalates, reaching its zenith when the load approximates 80% of the unit's rated capacity. This approach results in audible sound pressure figures even when the PSU is lightly loaded when the ambient temperature is very high, but, on the other hand, the proactive cooling strategy ensures a reliable operational landscape for the PSU.