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

Power Supply Quality

As part of our testing, we also check output parameters are within specifications, as well as voltage ripple and line noise.

The SeaSonic Focus GX-850 exhibits exemplary electrical performance metrics. It features tight voltage regulation on all three of its primary voltage rails (12V, 5V, and 3.3V), maintaining a regulation of less than 0.4%. The unit also boasts a low voltage ripple on the 12V rail, with a maximum recorded ripple of 28mV. In addition to this, the 3.3V and 5V rails demonstrate effective filtering, as indicated by a maximum voltage ripple of 22mV. These figures indicate a well-engineered electrical design that adheres to stringent performance criteria for a product of this class.

As part of our standard testing, we test the primary protections of all PSUs we review (Over Current, Over Voltage, Over Power, and Short Circuit). All of the protections of the SeaSonic Focus GX-850 engaged normally and within our expected parameters without any significant deviations.

Conclusion

The SeaSonic Focus GX-850 emerges as a robust ATX 3.0-compliant competitor in the crowded market of power supply units. Its build quality is exemplary, with an elegant exterior, custom embossed chassis decorations, and the convenience of fully modular cables. The internal components do not disappoint either, boasting high-grade Japanese capacitors throughout. The self-manufacture by SeaSonic ensures a meticulously designed unit, showcasing a redesigned Focus series platform aimed at ATX 3.0 compliance. The compact and clean design further accentuates its aesthetic and functional appeal while ensuring compatibility with all ATX-compliant cases.

Performance-wise, the Focus GX-850 excels in power quality. It exhibits remarkable voltage filtering, keeping the voltage ripples restrained below 28 mV even under strenuous loads. The load regulation is tight, with a variance of less than 0.5% on all voltage rails, showcasing its ability to deliver stable power under different load scenarios. Additionally, it comfortably meets the 80Plus Gold efficiency requirements, marginally missing the 80Plus Platinum certification at maximum load.

On the thermal front, the unit fares well with commendable thermal performance characterized by relatively low operating temperatures, a feature attributable to its high efficiency. Despite its substantial power output, the PSU maintains a cool operation, vital for long-term reliability and optimal performance. The noise level is another aspect where the Focus GX-850 shines; it operates nearly silently at low loads and room temperature. Although the noise level ascends with increased load, it remains within a tolerable range for most users.

The value proposition of the Focus GX-850 is somewhat nuanced. SeaSonic has undeniably elevated the performance metrics in the new Focus GX series over the preceding Focus Plus units. However, the current retail price of $168 positions it at a higher bracket compared to other 80Plus Gold certified ATX 3.0 units, never mind the $40 cheaper pre-ATX 3.0 version of the GX. The superior build quality and a reassuring 10-year warranty do provide some level of offset to the cost, but the heavy market competition due to a plethora of comparable products at or below its price point could pose a challenge for prospective buyers.

Ultimately, the SeaSonic Focus GX-850 ATX 3.0 is a formidable contender for those seeking a blend of quality, performance, and reliability, albeit at a premium price.