Seasonic CORE GX 850W ATX 3.1 80 Plus Gold Modular PSU Black
Seasonic
Seasonic CORE GX 850W ATX 3.1 80 Plus Gold Modular PSU Black
The Seasonic CORE GX 850W ATX 3.1 80 Plus Gold Modular PSU is designed for PC enthusiasts and system builders who need reliable, efficient power without overpaying for features they don't use. It delivers 850W of fully modular output with 80 PLUS Gold certification, making it a practical choice for high-performance builds that demand clean power and easy cable management. Native PCIe 5.1 support and a bundled legacy adapter mean it works with both current-generation and older graphics cards.
Why this product
ATX 3.1 and PCIe 5.1 ready
Compliant with the latest ATX 3.1 and PCIe 5.1 standards, it includes a native 12V-2x6 cable for next-generation graphics cards out of the box.
90% efficiency at 50% load
80 PLUS Gold certification means it achieves 90% efficiency at 50% system load, reducing waste heat and keeping electricity costs down.
Fully modular cable design
Every cable detaches completely, so unused connectors stay out of the case entirely, simplifying builds and improving airflow.
Quiet Hydro Dynamic Bearing fan
The 120 mm fan uses a Hydro Dynamic Bearing rated for 25,000 hours at 40 °C and pairs with Smart and Silent Fan Control to minimise noise during light loads.
Legacy GPU support included
A 12V-2x6 to 2× 8-pin PCIe adapter cable is included, so older graphics cards remain fully supported without buying extra accessories.
7-year worldwide warranty
Backed by Sea Sonic's 7-year worldwide manufacturer's warranty, giving long-term assurance for a component that sits at the heart of any build.
- Power Output850W
- Efficiency80 PLUS Gold (90% at 50% load)
- ModularityFully Modular
- ATX StandardATX 3.1
- PCIe StandardPCIe 5.1
- Warranty7-year worldwide
- Dimensions140 × 150 × 86 mm
- ColourBlack
- SKUSEA-755
- EAN4711173878476
- Compatible with ATX and EPS form-factor motherboards and cases.
- Supports PCIe 5.1 graphics cards via the included native 12V-2x6 cable.
- Compatible with legacy GPUs using the included 12V-2x6 to 2× 8-pin PCIe adapter cable.
- Fully modular design — all cables must be sourced from the included set or verified Seasonic-compatible replacements, as pin layouts vary between brands.
- Measures 140 × 150 × 86 mm; verify your case supports a standard ATX PSU at this depth before purchasing.
Best for
- High-end GPU builds: 850W headroom and native PCIe 5.1 support make it suitable for systems running current-generation discrete graphics cards.
- Builders upgrading their PSU without changing their GPU: The included legacy adapter removes the need to buy a separate cable when pairing this unit with an older graphics card.
- Noise-sensitive builds: Smart and Silent Fan Control reduces fan activity at low loads, making it well-suited to quiet workstation or gaming setups.
- Long-term ownership: The 7-year worldwide warranty and 25,000-hour fan life rating suit buyers who keep components for many years.
- Clean cable-management builds: Full modularity means only the cables actually needed are installed, keeping the interior tidy.
Trade-offs
- Very high-wattage workloads: The range tops out at 850W in this configuration; builds requiring more than that should consider a higher-output unit.
- White-themed builds: This variant is black only; a white colour option exists in the CORE GX ATX 3.1 range but is a separate product.
- Budget-priority builders: 80 PLUS Gold efficiency and a 7-year warranty carry a cost premium over Bronze-rated alternatives; buyers with strict budget constraints may find lower-tier options more appropriate.
The updated Seasonic CORE GX ATX 3.1 Series complies with the latest ATX 3.1 and PCIe 5.1 standards and includes four output ranges from 1000 W to 650 W in both black and white colors. Catering to a broad spectrum of PC enthusiasts and system builders, these power supplies provide a fine balance between cost and performance. The 80 PLUS® Gold certified Seasonic's Core GX line is a fully modular design equipped with black cables featuring a braided pattern. These power supplies are solid performers for a large range of applications, where a 120 mm Hydro Dynamic Bearing fan is combined with Seasonic's Smart and Silent Fan Control to ensure the optimal cooling performance at the lowest possible noise level.
These quality power supplies are backed up by Sea Sonic's 7-year worldwide manufacturer's warranty. The CORE GX ATX 3.1 (2024) Series achieves 80 PLUS® Gold certification with its 90 % efficiency at 50 % system load.
To ensure compatibility with older GPUs, the CORE GX ATX 3.1 includes a 12V-2x6 to 2× 8-pin PCIe adapter cable. It delivers reliable power up and works seamlessly with graphics cards from previous generations. This cable makes it easy to upgrade your PSU without changing your GPU—perfect for users who want next-gen power with legacy support.
In Sea Sonic's patented design feature full modularity comes hand-in-hand with the extensive use of SMD technology to increase the overall performance and reliability of this power supply. The simple and inventive layout scheme helps to attain unsurpassed quality and performance, where efficiency is further enhanced by minimized line resistance, reduced voltage drop and lower impedance.
General
| Brand | Seasonic |
|---|---|
| Model | SRP-CGX851-A5A32SF |
| Colour | Black |
| Form Factor | ATX/EPS |
| Dimensions | 140 × 150 × 86 mm |
Power & Efficiency
| Power Output | 850W |
|---|---|
| Efficiency Rating | 80 PLUS Gold |
| Efficiency at 50% Load | 90% |
| ATX Standard | ATX 3.1 |
| PCIe Standard | PCIe 5.1 |
| Modularity | Fully Modular |
| Cable Type | Individual Black Cables with Braided Pattern |
Cooling
| Fan Size | 120 mm |
|---|---|
| Fan Bearing | Hydro Dynamic Bearing |
| Fan Control | Smart and Silent Fan Control |
| Fan Life Expectancy | 25,000 hours at 40 °C, 15%–65% RH |
Warranty & Compliance
| Warranty | 7-year worldwide manufacturer's warranty |
|---|---|
| Certifications | 80 PLUS Gold, ATX 3.1, PCIe 5.1 |
Shipping
All our products are shipped from the United Kingdom within 24 to 48 hours of purchase. See our Shipping and Returns page for full details.
Returns
- Tech Syndicate offers a full money-back guarantee on all purchases made in our store. If you are not satisfied with your purchase, we will provide a full refund, no questions asked.
- Refunds are available within 45 days of delivery.
- After the 45-day period you are no longer eligible for a refund, so we encourage you to try the product within the first few weeks to make sure it fits your needs.