The Seasonic Focus GX-850 V4 holds full power at 46°C and is ready for ATX v3.1 and PCIe 5.1, with high build quality and good ripple suppression. Overall performance is where it falls short, and the fan speed profile needs work. TechPowerUp and Hardware Busters both criticized its transient response and its efficiency under light loads. One user on Facebook reported returning multiple PSUs before settling on this model. It suits buyers who weigh build quality and features above peak performance.
Full review
Lacks heatsinks, runs hotter than before
Seasonic's Focus GX-850 V4 represents a significant evolution in their power supply lineup, featuring a redesigned PCB and OptiSink technology that promises improved heat dissipation and component spacing. The unit measures 140mm deep, making it compatible with all ATX cases, and includes a 135mm fluid dynamic bearing fan with digital hybrid control. According to Hardware Busters' crmaris, the new PCB design allows for better airflow, though he noted that the lack of proper heatsinks on vital components contributes to higher operating temperatures. The build quality is solid, with premium Japanese capacitors rated for 105°C and a full array of protections including OCP, OVP, UVP, SCP, OTP, and OPP. Tom's Hardware's review of the Seasonic Focus Plus Gold 850 highlighted the same compact design, calling the unit "super compact, allowing its installation even in small sized chassis."
The Focus GX-850's design includes a 12V-2×6 cable and a 12V rail capable of delivering 70A (840W), which is 97% of the unit's total output. The fan control system offers three modes: fanless, silent, and cooling, with the S3FC (selectable semi-passive operation) allowing users to customize cooling needs. The unit also features gold-plated connectors, a 10-year warranty, and a peak power output of 968W. However, crmaris from Hardware Busters noted that despite the improved PCB layout, the previous GX-850 unit achieved slightly higher overall performance. The unit's compact size is a major advantage, but the distance between the 4-pin Molex connectors is under 150mm, which may be limiting for some users. Additionally, the fan speed profile needs improvement: HWBusters' crmaris reported that "the PSU's average noise output is not as low as I expected," and suspects that the lack of proper heatsinks on vital parts plays a role.
Performance and Efficiency
Efficiency testing reveals that the Seasonic Focus GX-850 V4 achieves 80+ Gold certification, with peak efficiency reaching 92% at 50% load. However, performance under light loads is less impressive, with crmaris from Hardware Busters noting that efficiency under light loads is not competitive. The unit's power factor readings are mediocre, and it exhibits sky-high inrush currents, which are particularly problematic at 230V. The low starting voltage level of the 12V rail affects load regulation, and the unit struggles with transient response at 12V and 3.3V under ATX v3.1 transient loads. The 12V rail's load regulation at 20W load is particularly concerning, as it indicates that the unit may not maintain stable voltage under light loads, which can be critical for system stability.
In terms of ripple suppression, the Focus GX-850 V4 performs well, with good suppression at 5V and 12V rails, though it is still not competitive with top-tier units. The unit's hold-up time is adequate, but its inrush current testing revealed that it draws excessive current during startup, which can cause issues with some power supplies and potentially lead to premature wear. The vampire power consumption at 230V is also high, which is a concern for users looking to minimize energy waste. The unit's efficiency is acceptable for most users, but it falls short of the performance expected from a high-end PSU, particularly in the 20-30% load range where many users operate their systems. The unit's performance under sustained loads is better, with full power delivered at 46°C, but the transient response at 12V and 3.3V is still problematic, indicating that the unit may struggle with sudden load changes.
Noise and Thermal Performance
Noise output is a significant concern with the Seasonic Focus GX-850 V4, with crmaris from Hardware Busters noting that the average noise output is not as low as expected. The fan speed profile needs improvement, and users have reported that the fan is particularly noisy under light load gaming conditions. A reader who bought the unit told Hardware Busters in the review's comments that the fan noise is 'absolutely insane under light load gaming,' and said he had ordered a be quiet! Power Zone 2 850W to replace it. The unit's thermal performance is mixed, with the OptiSink design improving airflow but not sufficiently reducing noise. The fan control system offers three modes, but the transition between modes can be abrupt, leading to sudden increases in noise levels. The unit's ability to maintain low temperatures under load is acceptable, but the fan's aggressive behavior under light loads is a major drawback. The 10-year warranty, while generous, may be a result of the manufacturer's need to keep fan speeds low to prevent overheating, which can lead to long-term reliability issues.
The fan's performance is further complicated by the unit's design, which lacks proper heatsinks on vital components. This design choice, while potentially cost-effective, leads to elevated operating temperatures, particularly under sustained loads. The fan speed profile is not optimized for quiet operation, and the unit's noise output is higher than what users expect from a Gold-certified PSU. The lack of a fanless mode at low loads is particularly problematic, as it forces the fan to run continuously, even when the system is idle. The unit's thermal performance is adequate, but the noise levels are a significant deterrent for users who value quiet operation. The fan's behavior under different load conditions is inconsistent, with sudden changes in fan speed that can be disruptive in quiet environments.
Real-World Performance Testing
HWBusters lists "Delivered full power at 46°C" among the Seasonic Focus GX-850 V4's pros, which is a positive sign for thermal performance. However, its performance under light loads is less impressive, with crmaris from Hardware Busters noting that the unit's efficiency under light loads is not competitive. The unit's ability to maintain stable voltage under varying loads is mixed, with tight load regulation at 5V but loose regulation at 12V. The unit's performance under sustained loads is acceptable, but the transient response issues are a significant drawback for users who require consistent power delivery.
Testing by TechPowerUp revealed that the unit's efficiency is acceptable but not exceptional, with peak efficiency reaching 92% at 50% load. The unit's performance under sustained loads is better, with full power delivered at 46°C, but the transient response at 12V and 3.3V is still problematic.
OptiSink layout permits airflow without pushing fan speed
HWBusters' crmaris praised the Seasonic Focus GX-850 V4's build quality but pointedly refused to credit the 10-year warranty: "This is why I no longer care for the provided warranty, as long as it exceeds 2-3 years," arguing that a long warranty forces a manufacturer to play it safe with the fan speed profile. The unit's fully modular design is also a major plus, allowing users to reduce cable clutter and improve airflow. The OptiSink technology is noted as a significant improvement, with crmaris from Hardware Busters stating that it allows for lots of room between components, enabling high airflow without pushing fan speeds. The unit's ability to deliver full power at 46°C is also appreciated, as it indicates good thermal management. The 12V rail's tight load regulation at 5V and the good ripple suppression are also highlighted as positive aspects. The unit's compatibility with ATX v3.1 and PCIe 5.1 standards is a major selling point, particularly for users building systems with the latest high-power graphics cards and processors. Overall performance, though, is not superior to the competition: HWBusters found that "the NZXT C850 costs way less, at $120 at the time of the review, and offers notably better performance in most sections," that the Corsair RM850x gives about 5% more performance for $10 more, and that the Super Flower Leadex VII XG leads the GX-850 V4 by 7%.
The unit's compact size is another feature that reviewers appreciate, with Tom's Hardware calling a 140mm-deep Focus "very compact." The digital hybrid fan control system is seen as a significant improvement over previous models, offering three modes: fanless, silent, and cooling. Noise, however, is not a strength: HWBusters' crmaris wrote that Seasonic "should go after higher performance with this new PCB design and lower the unit's overall noise, which is pretty high for this category's standards." The unit's compatibility with both ATX v3.1 and PCIe 5.1 standards is also seen as a major advantage, particularly for users building systems with the latest high-power components. The unit's performance under sustained loads is also considered acceptable, with full power delivered at 46°C, which is a positive sign for thermal management.
Noisy under light-load gaming, per owners
Despite its many strengths, the Seasonic Focus GX-850 V4 has several notable shortcomings. The most significant issue is its noise output, which is higher than expected for a Gold-certified PSU. Users have reported that the fan is particularly noisy under light load gaming conditions, prompting some to seek quieter alternatives. The unit's transient response at 12V and 3.3V under ATX v3.1 transient loads is also problematic, with crmaris from Hardware Busters noting that this is a major drawback. The unit's efficiency under light loads is not competitive, and the low starting voltage level of the 12V rail affects load regulation. The power factor readings are mediocre, and the inrush currents are sky-high, particularly at 230V.
The unit's design also has several flaws that detract from its overall value. The distance between the 4-pin Molex connectors is under 150mm, which may be limiting for some users. The lack of proper heatsinks on vital components leads to elevated operating temperatures, which can affect long-term reliability. The unit's performance is not competitive with other high-end PSUs in the same price range, with crmaris from Hardware Busters noting that the NZXT C850 costs $120 and offers notably better performance, while the Corsair RM850x is 10 dollars more expensive but provides about 5% higher overall performance. The unit's MSRP is also higher than some competitors, making it less attractive for budget-conscious users.
Delivers 840W across a single 70A 12V rail
The Seasonic Focus GX-850 V4 is best suited for users who prioritize build quality and warranty over absolute performance and noise levels. It's particularly ideal for enthusiasts who are building systems with the latest high-power components and need a PSU that's compatible with ATX v3.1 and PCIe 5.1 standards. The unit's 10-year warranty is a major selling point for users who want long-term reliability and peace of mind. The fully modular design is also appealing to users who want to reduce cable clutter and improve airflow in their systems. The unit's ability to deliver full power at 46°C makes it suitable for users who need consistent power delivery under sustained loads. The compact size is also a plus for users with small chassis or those who want to maximize airflow. However, users who prioritize quiet operation or need optimal efficiency under light loads should look elsewhere, as the unit's noise output and efficiency under light loads are not competitive.
The unit is also a good choice for users who are building systems with the latest high-power graphics cards and processors, particularly those that require ATX v3.1 and PCIe 5.1 compliance. The unit's 12V rail is capable of delivering 70A (840W), which is 97% of the unit's total output, making it suitable for high-end systems. The unit's gold-plated connectors and premium Japanese capacitors are also appealing to users who want a high-quality PSU. However, users who are building systems with lower power requirements or who are more concerned about noise levels should consider alternative PSUs. The unit's performance is acceptable for most users, but it falls short of the performance expected from a high-end PSU, particularly in the 20-30% load range where many users operate their systems.
Trails the Super Flower Leadex VII XG by 7%
When compared to alternatives like the NZXT C850, which costs $120 and offers notably better performance, the Seasonic Focus GX-850 V4 is less competitive in terms of value. The Corsair RM850x, which is $10 more expensive, provides about 5% higher overall performance, making it a better choice for users who prioritize performance over warranty. The Super Flower Leadex VII XG is the best-performing unit in this category, with a 7% performance gap with the GX-850 V4. The unit's performance under sustained loads is acceptable, but the transient response issues and noise output are significant drawbacks. The unit's efficiency under light loads is not competitive, and the power factor readings are mediocre. The inrush currents are also sky-high, particularly at 230V, which can cause issues with some power supplies and potentially lead to premature wear.
In comparison to other Gold-certified PSUs, the Seasonic Focus GX-850 V4 falls short in several key areas. While it offers good build quality and a generous 10-year warranty, its performance under light loads is not competitive, and its noise output is higher than expected. The unit's efficiency under light loads is particularly concerning, as it indicates that the unit may not be suitable for users who operate their systems at low loads. The unit's transient response issues are also a significant drawback, as they can affect system stability under sudden load changes.
Strengths
- +Delivered full power at 46°C ATX v3.1 and PCIe 5.1 ready
- +High build quality with OptiSink technology for better heat dissipation
- +Good ripple suppression
- +Tight load regulation at 5V
- +3x PCIe on dedicated cables and 1x 12+4-pin PCIe connectors
Watch-outs
- −Increased MSRP
- −Not competitive overall performance
- −Fan speed profile needs improvement
Rating sources
“The Seasonic GX-850 V4 is expensive at $140, but the NZXT C850 costs way less, at $120 at the time of the review, and offers notably better performance in most sections.”
Our 3.5 score is the average of these published ratings. Ratings marked * were derived from the reviewer’s written analysis or video transcript — the publisher didn’t print an explicit numeric score, so we inferred one from their own words. Click through to verify. More about methodology.
