here!
I’m your shopping assistant for PC builds, upgrades, and everything tech.
Got questions? Ask away!
Start a conversation
SeaSonic FOCUS GX ATX 3 (2024) GX-850 850 W ATX3.1 80 PLUS GOLD Nvidia RTX 40 Super/50 Certified Full Modular Power Supplies
- ATX3.1
- Nvidia RTX 40 Super/50
- Full Modular
- 80 PLUS GOLD Certified
- 100 - 240 V 50/60 Hz
+
+
Overview
Specs
Reviews (4,610)
See all Q & A 
Any questions? Ask CelesteSM will help you find out quickly.
Try me now
Warranty & Returns
Warranty, Returns, And Additional Information
Warranty
- Limited Warranty period (parts): 1 year
- Limited Warranty period (labor): 1 year
- Read full details
Return Policies
- Return for refund until: January 31, 2026
- Return for replacement until: January 31, 2026
- This item is covered by Newegg.com's Extended Holiday Return Policy.
- Read full return policy for details.
We want to ensure your holiday shopping this year is hassle-free. That’s why we’re automatically extending our return policies on almost every product! For purchases placed between November 1st, 2025 and December 31, 2025 you will have until January 31, 2026 to return your product.
Manufacturer Contact Info
- Manufacturer Product Page
- Manufacturer Website
- Support Phone: 1-626-969-9966
- Support Website
- View other products from Seasonic
LOADING...
LOADING...
The SeaSonic FOCUS GX ATX 3 (2024) GX-850 is an 850W, fully modular ATX 3.1 power supply with 80 PLUS Gold certification and support for Nvidia RTX 40 Super/50 graphics cards. It is suitable for performance gaming PCs, creator workstations, and custom desktop builds requiring modern GPU power delivery.
Recommended For
- PC gamers building a single-GPU system with a modern Nvidia RTX 40 Super or RTX 50 graphics card who want ATX 3.x support and a native high-power GPU connection.
- Single-GPU gaming and content-creation workstations that combine a high-end processor with one demanding graphics card and need 850 W of ATX power capacity.
- Builders using a mid-tower or other ATX-compatible case with limited PSU depth, because the 140 mm-long chassis is shorter than many high-wattage ATX power supplies.
- PC builders who regularly replace or upgrade components and want full-modular cabling so unused power cables can be removed from the system.
- Users planning to keep the same PSU across multiple future PC upgrades and who value Seasonic's advertised 10-year warranty and ATX 3.x compatibility.
Real-World Use Scenarios
- Building a modern gaming PC with a high-end RTX 40- or RTX 50-series graphics card: the ATX 3.1 design and native 12V-2x6 connection let the user connect the GPU directly, reducing reliance on adapter cables and helping the system handle short power spikes during demanding games. ([seasonic.com](https://seasonic.com/atx3-focus-gx/))
- Assembling a performance-focused ATX gaming or creator PC: the 850 W capacity provides practical headroom for a single high-end GPU, a mainstream or enthusiast CPU, multiple storage drives, and additional cooling without immediately requiring a higher-wattage unit; final suitability still depends on the exact component power requirements. ([seasonic.com](https://seasonic.com/atx3-focus-gx/))
- Installing a power supply in a mid-tower or other case with limited PSU depth: the 140 mm-long chassis is easier to accommodate than many longer high-wattage units, while full modular cabling lets the builder install only the power leads the system needs and route fewer unused cables. ([seasonic.com](https://seasonic.com/atx3-focus-gx/))
- Upgrading an older gaming PC to a current-generation GPU: the included modern GPU power connection can simplify the upgrade by avoiding some legacy adapter setups, while the fully modular layout makes it easier to replace or rearrange cables during the rebuild. ([seasonic.com](https://seasonic.com/wp-content/uploads/2024/07/ATX3.1-FOCUS-GX.pdf?utm_source=openai))
- Running a mixed-use desktop for web work, media, and occasional gaming: at light loads, the selectable semi-passive mode may limit fan activity, but real-world noise is not guaranteed to be silent because independent testing and user reports describe an aggressive fan profile during some GPU gaming loads. ([hwbusters.com](https://hwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-review/))
Spec Summary
| Attribute | Value |
|---|---|
| Best For | ATX desktop PC builds requiring an 850 W, ATX 3.1, full-modular power supply with 80 PLUS Gold efficiency |
| Power Output And Efficiency | 850 W maximum output with 80 PLUS Gold certification for 100–240 V input at 50/60 Hz |
| Modularity And Connectors | Full-modular design with 11 PSU connectors, including a 24-pin ATX connector and ATX cable connectivity |
| Cooling | Air-cooled by one 135 mm fluid dynamic bearing fan |
| Physical Dimensions | 140 mm long × 150 mm wide × 86 mm high, with a maximum PSU length of 150 mm |
| Model Identifiers | SeaSonic FOCUS GX ATX 3 (2024), model GX-850 |
Reference Q&A
Q: Should I buy the Seasonic FOCUS GX-850 ATX 3.1 or the Corsair RM850x SHIFT?
A: Choose the Seasonic FOCUS GX-850 when you want a compact 140 mm PSU with a conventional connector layout that fits standard ATX cases. Choose the Corsair RM850x SHIFT when side-mounted modular connections and Zero RPM fan operation are more important, provided your case has about 30 mm of clearance beside the PSU. Both provide 850 W, full modular cabling, ATX 3.1 support, and a native 12V-2x6 GPU cable.
Q: Is the Seasonic FOCUS GX-850 better than the GX-750 for a gaming PC?
A: The GX-850 is the better choice for a system with a higher-power GPU, a power-hungry CPU, or planned upgrades because it provides 100 W more total capacity and up to 840 W on the 12 V rail. The GX-750 is sufficient when the system’s estimated peak consumption leaves comfortable headroom below 750 W. Both models are fully modular, 80 PLUS Gold certified, ATX 3.1 compliant, and include a native 12V-2x6 cable.
Q: Should I get the Seasonic FOCUS GX-850 or the GX-1000?
A: Choose the GX-850 for most single-GPU gaming and workstation builds where 850 W provides adequate calculated headroom. Choose the GX-1000 for flagship graphics cards, high-end CPUs, sustained heavy workloads, or additional upgrade headroom. The GX-1000 supplies up to 996 W on the 12 V rail, compared with 840 W for the GX-850, but both use the same ATX 3.1, PCIe 5.1, full-modular, 80 PLUS Gold design.
Q: Is the 2024 Seasonic FOCUS GX-850 worth choosing over the older ATX 3.0 version?
A: For a new build using a recent graphics card, the 2024 version is the more direct fit because it is specified for ATX 3.1 and PCIe 5.1 and includes a native 12V-2x6 cable. The older ATX 3.0 version remains usable when already installed or available at a substantially lower price, but the upgrade does not increase the rated 850 W capacity. Confirm the exact revision because Seasonic FOCUS GX versions can have similar retail names.
Q: Is the Seasonic FOCUS GX-850 suitable for a compact PC build?
A: It is a practical choice for compact ATX or space-constrained builds because the PSU is 140 mm long, fully modular, and uses a standard rear-facing connector layout. It is less convenient than a purpose-built SFX power supply for truly small-form-factor cases, so verify that the case supports an ATX PSU and has room for the included cable bend radius.
Q: Can this PSU power a gaming PC with an Nvidia RTX 40 Super or RTX 50 graphics card?
A: Yes, the 850 W SeaSonic FOCUS GX ATX 3 (2024) is designed for Nvidia RTX 40 Super and RTX 50 graphics cards. It is suitable for many single-GPU gaming systems, but you should still confirm the graphics card manufacturer's recommended PSU wattage and account for the CPU and other components.
Q: Will this 150 mm PSU fit in my PC case?
A: The PSU measures 150 mm wide, 86 mm high, and 140 mm deep, with a listed maximum PSU length of 150 mm. It should fit cases that support standard ATX power supplies with at least 150 mm of PSU clearance, but you should also check room for the modular cables, drive cages, radiators, and cable routing.
Q: Is this power supply a good choice for a modern high-end gaming PC?
A: It is a strong fit for many modern single-GPU gaming PCs because it provides 850 W, ATX 3.1 support, full modular cabling, and 80 PLUS Gold efficiency. It may be less suitable for systems with an extremely high-power processor, multiple GPUs, or substantial future expansion, where a higher-wattage PSU may provide more headroom.
Q: What are the benefits and trade-offs of this PSU being fully modular?
A: A fully modular design lets you connect only the cables your build requires, which can simplify cable management and improve available airflow around the PSU area. The trade-off is that installation requires selecting and connecting the appropriate modular cables, and only cables supplied for this specific PSU should be used.
Q: Is this PSU efficient and likely to be quiet?
A: The PSU is 80 PLUS Gold certified and uses a 135 mm Fluid Dynamic Bearing fan. The certification indicates a high-efficiency design, while the FDB fan supports cooling with potentially lower mechanical noise than simpler fan-bearing designs. Actual noise depends on system load, temperature, case airflow, and the PSU's fan curve.
Q: Is the Seasonic FOCUS GX-850 ATX 3.1 a good choice for a high-end gaming PC?
A: Yes, it is a suitable choice for many high-end gaming systems because it provides 850 W, ATX 3.1 support, full modular cabling, and compatibility with current Nvidia RTX 40 and RTX 50-series graphics cards. Confirm that 850 W meets the specific CPU and GPU manufacturer recommendations for your build.
Q: Is the GX-850 worth buying compared with cheaper 850 W ATX 3.1 power supplies?
A: It can be worth buying when reliability, Seasonic’s platform, and current GPU connectivity are priorities. Community comparisons also indicate that cheaper ATX 3.0 or ATX 3.1 models may provide better value, so the GX-850 is less compelling when its price is substantially higher than similarly rated alternatives.
Q: Is the Seasonic GX-850 quiet enough for a quiet PC?
A: It has a hybrid fan mode that can stop the fan at low load, but reported noise is mixed. Some users describe the fan as quiet in hybrid mode, while others report an aggressive or loud fan curve when the fan is running. It is therefore a better fit for users who prioritize ATX 3.1 support over consistently silent operation.
Q: Does the GX-850 make sense for a mid-range PC or a lower-power graphics card?
A: Usually, it is more capacity than necessary for a mid-range system. Community discussions note that ATX 3.x and 850 W are most useful when supporting higher-power modern GPUs or future upgrades; for a lower-power build, a less expensive 650 W or 750 W unit may be sufficient if it meets the component requirements.