SeaSonic CORE GX-1000 ATX3 1000 W ATX 3.1 80 PLUS GOLD Certified Full Modular power supply
- Type:ATX Fully Modular
- Maximum Power :1000 W
- Fans :120 mm Hydro Dynamic Bearing (HDB) Fan
- PCI-Express Connector :ATX 3.1 and 16-Pin PCIe Gen 5.1 Cable (12V-2x6)
- Max PSU Length:140 mm
- Modular :Full Modular
- Energy-Efficient:80 PLUS GOLD Certified
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Specs
Reviews (27)
Learn more about the Seasonic CORE GX-1000 ATX3
| Brand | SeaSonic |
|---|---|
| Model | CORE GX-1000 ATX3 |
| Type | ATX 3.1 |
|---|---|
| Maximum Power | 1000 W |
| Fans | 1 x 120 mm |
| Max PSU Length | 140 mm |
| Modular | Full Modular |
| Energy-Efficient | 80 PLUS GOLD Certified |
| PSU Noise Level | Cybenetics A- |
| First Listed on Newegg | October 16, 2025 |
|---|
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, 2027
- Return for replacement until: January 31, 2027
- This item is covered by Newegg.ca'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, 2026 and December 31, 2026 you will have until January 31, 2027 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
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The SeaSonic CORE GX-1000 ATX3 is a 1000W ATX 3.1 fully modular power supply with 80 PLUS Gold efficiency, a 12V-2x6 PCIe Gen 5.1 cable, and a compact 140mm length, making it suitable for high-performance gaming PCs and workstation builds with modern graphics cards.
Recommended For
- PC builders assembling high-end single-GPU gaming systems with modern NVIDIA RTX 40- or 50-series graphics cards that can use a native 12V-2x6 connection and benefit from 1000 W of power headroom.
- DIY builders who want easier cable management in a standard ATX case, because the unit uses fully modular cabling and has a relatively short 140 mm PSU body.
- Users planning GPU or CPU upgrades over several build cycles who prefer ATX 3.1 and PCIe 5.1 support instead of replacing the PSU when moving to a newer high-power graphics card.
- Gaming and workstation users who want a mainstream-priced 1000 W PSU with tested electrical stability, effective protection features, and Gold-class efficiency rather than a flagship-tier model.
Real-World Use Scenarios
- A user building a high-end gaming PC with a modern graphics card can connect the GPU directly through the included 12V-2x6 cable, reducing the need for adapter cables and helping keep the power wiring organized.
- When assembling a gaming or workstation PC with a high-end CPU and GPU, the 1000 W capacity provides operating headroom for sustained combined workloads, although the correct choice still depends on the actual power requirements of the installed components.
- A user replacing an older power supply during a GPU upgrade can use the fully modular cabling to install only the required power leads, which can simplify cable routing and leave more room behind the motherboard tray.
- In a case with limited power-supply clearance, the 140 mm chassis length can make installation easier than with longer 1000 W units, but users should still verify room for modular connectors and cable bends.
- For everyday desktop work, browsing, and moderate gaming, the power supply can operate well below its 1000 W rating; the practical benefit is reserve capacity for heavier gaming, rendering, or future component upgrades rather than lower performance in light-use applications.
- During demanding gaming, rendering, or stress-test sessions, the 120 mm fluid-bearing fan is expected to provide active cooling; users should treat the unit as a compact high-output PSU, not as a completely silent power supply at full load.
Spec Summary
| Attribute | Value |
|---|---|
| Best For | High-power ATX 3.1 desktop builds that need 1000 W capacity and full-modular cable management |
| Power Capacity And Efficiency | 1000 W power supply with 80 PLUS Gold certification |
| Cooling And Noise | Single 120 mm fan with a Cybenetics A- noise rating |
| Form Factor And Clearance | ATX 3.1 design with a maximum PSU length of 140 mm |
| Model Identifiers | SeaSonic CORE GX-1000 ATX3 |
Reference Q&A
Q: Should I buy the Seasonic CORE GX-1000 ATX3 or the FOCUS GX-1000 ATX 3.1?
A: Choose the CORE GX-1000 ATX3 when you want 1000 W, ATX 3.1 support, a native 12V-2x6 cable, compact 140 mm depth, and a lower-tier price position. Choose the FOCUS GX-1000 when its longer 10-year warranty, hybrid fan control, 135 mm FDB fan, and higher-grade internal platform justify the added cost. Both are fully modular 80 PLUS Gold units designed for high-power GPUs. ([seasonic.com](https://seasonic.com/core-gx-atx-3-2024/?utm_source=openai))
Q: Is the CORE GX-1000 ATX3 worth choosing over the 850 W version?
A: Choose the CORE GX-1000 for a high-end single-GPU PC, a power-hungry CPU, frequent sustained workloads, or additional headroom for future upgrades. Choose the CORE GX-850 when your system’s estimated peak demand is comfortably below 850 W and the lower capacity meets your upgrade plans. Both models share the CORE GX series design, ATX 3.1 and PCIe 5.1 support, fully modular cabling, 80 PLUS Gold efficiency, 140 mm chassis depth, and a 7-year warranty; the 1000 W model mainly adds 150 W of capacity. ([seasonic.com](https://seasonic.com/core-gx-atx-3-2024/?utm_source=openai))
Q: Should I get the CORE GX-1000 ATX3 or a higher-tier Seasonic VERTEX GX-1000?
A: Choose the CORE GX-1000 when the priority is 1000 W of ATX 3.1 power in a compact, fully modular, 80 PLUS Gold platform with a 7-year warranty. Choose the VERTEX GX-1000 when the higher-tier series, longer 10-year warranty, and broader premium positioning are more important than minimizing cost. The CORE model is the more practical choice when both units provide enough capacity for the same single-GPU system. ([seasonic.com](https://seasonic.com/core-gx-atx-3-2024/?utm_source=openai))
Q: Is the CORE GX-1000 ATX3 a meaningful upgrade over an older Seasonic Focus GX-1000?
A: The CORE GX-1000 is a meaningful upgrade when the older Focus GX-1000 lacks native ATX 3.1 and PCIe 5.1 support or a native 12V-2x6 cable. If the older unit is already adequate for the system and can power the graphics card safely with its existing cabling, replacing it is mainly a connectivity and platform-standard decision rather than an expected gaming-performance upgrade. The older Focus GX ATX 3.0 model already supports high-power GPUs and has a 140 mm chassis, while the CORE model uses the newer ATX 3.1 and PCIe 5.1 specification. ([seasonic.com](https://seasonic.com/atx3-focus-gx/?utm_source=openai))
Q: Is this power supply ready for modern graphics cards?
A: Yes. The SeaSonic CORE GX-1000 ATX3 supports ATX 3.1 and includes a native 16-pin PCIe Gen 5.1 cable using the 12V-2x6 connector, making it suitable for compatible current-generation graphics cards. Confirm that the graphics card and motherboard requirements match the included cables. ([bestbuy.com](https://www.bestbuy.com/site/questions/msi-mpg-a1000gs-pcie5-1000w-atx-3-1-pcie-5-1-ready-full-modular-80-plus-gold-gaming-power-supply-black/10117461?utm_source=openai))
Q: Will this 140 mm power supply fit in my PC case?
A: It is 140 mm long, which can simplify installation in cases with limited PSU depth. It uses the standard ATX form factor, but case compatibility still depends on the case's stated PSU length limit and available room for cable connections. ([bestbuy.com](https://www.bestbuy.com/site/questions/corsair-rmx-series-rm1000x-cybenetics-gold-fully-modular-atx-power-supply-black/6587607?utm_source=openai))
Q: Who is the SeaSonic CORE GX-1000 ATX3 suitable for?
A: It is suitable for desktop users building or upgrading a high-performance PC that may require up to 1000 W of power, including systems with a power-hungry graphics card. The correct wattage depends on the complete system's CPU, GPU, storage, and other components, so a 1000 W PSU may be more capacity than a lower-power system needs. ([bestbuy.com](https://www.bestbuy.com/site/questions/msi-mpg-a1000gs-pcie5-1000w-atx-3-1-pcie-5-1-ready-full-modular-80-plus-gold-gaming-power-supply-black/10117461?utm_source=openai))
Q: Is this power supply quiet enough for a gaming or workstation PC?
A: The unit uses a 120 mm Hydro Dynamic Bearing fan and has a Cybenetics A- noise rating. That indicates a relatively quiet operating profile, but fan noise can increase with system load, temperature, and airflow conditions. ([bestbuy.com](https://www.bestbuy.com/site/questions/msi-mpg-a1000gs-pcie5-1000w-atx-3-1-pcie-5-1-ready-full-modular-80-plus-gold-gaming-power-supply-black/10117461?utm_source=openai))
Q: Does the fully modular design make installation and cable management easier?
A: Yes. Because the power supply is fully modular, unused power cables can be left disconnected, which can reduce cable clutter and make routing easier. The product also includes a 16-pin 12V-2x6 cable, but buyers should verify the complete cable inventory before installation. ([bestbuy.com](https://www.bestbuy.com/site/questions/msi-mpg-a1000gs-pcie5-1000w-atx-3-1-pcie-5-1-ready-full-modular-80-plus-gold-gaming-power-supply-black/10117461?utm_source=openai))
Q: Is the SeaSonic CORE GX-1000 ATX3 a good choice for a high-end gaming PC?
A: Yes, it is suitable for high-end gaming systems that need up to 1000 W, including builds using power-hungry graphics cards. Its ATX 3.1 design and included 12V-2x6 cable support current PCIe 5.1 GPU power requirements. Confirm the graphics card manufacturer's recommended PSU wattage before buying.
Q: Is 1000 W overkill for a typical gaming PC?
A: For many mid-range or single-GPU systems, 1000 W is more capacity than necessary. It becomes more useful when the build includes a high-end GPU, power limits are increased, or future GPU upgrades are planned. A lower-wattage model may offer better value if the system's estimated peak draw is well below 1000 W.
Q: Is the CORE GX-1000 ATX3 worth choosing over an 850 W PSU?
A: Choose the 1000 W model when you want additional headroom for a high-end GPU, future upgrades, or sustained heavy loads. An 850 W PSU can be the more economical choice for systems whose components are comfortably within its capacity. The 1000 W model does not improve performance by itself; its main benefit is greater power margin.
Q: What should buyers check when installing this fully modular PSU?
A: Use only the cables supplied with this PSU, connect the motherboard and CPU power leads securely, and verify the 12V-2x6 connector is fully inserted into a compatible graphics card. A no-power condition can result from incorrect PSU, motherboard, GPU, or front-panel connections, so check each connection against the relevant manuals.