Seasonic
Seasonic FOCUS GX-850 850 W power supply
An 850 W ATX power supply with full modular cabling, 80 PLUS Gold efficiency and a fan that stops below 30 % load
- ColorBlack
- TypeATX12V / EPS12V
- Maximum Power850 W
- Fans1
- ModularFull Modular
- Energy-Efficient80 PLUS GOLD Certified
- 850 W output supports demanding multi-GPU builds
- 80 PLUS Gold certification reduces energy waste
- Full modular design keeps cables tidy
- Semi-passive fan stays off until 30 % load
- Compact 140 mm depth fits smaller cases
FOCUS GX-850 850 W ATX supply
The Seasonic FOCUS GX-850 is an 850 W ATX12V and EPS12V power supply with full-modular cabling. It carries 80 PLUS Gold certification and a compact depth of 140 mm. The unit suits builders who need high output in a shorter chassis.
Thermals, noise and power draw
A 120 mm fluid-dynamic-bearing fan stays off until the load reaches 30 percent thanks to the S3FC circuit. Below that threshold the supply runs silently while maintaining tight voltage regulation. At typical loads the single fan spins at low speed, keeping noise minimal.
Sustained-load behaviour
Under continuous demand the fan ramps up to maintain stable temperatures across the 850 W rating. The platform is rated for an MTBF above 100,000 hours and meets ErP Lot 6 efficiency requirements. It supports multi-GPU configurations without exceeding its thermal envelope.
Highlights
- 850 W output supports demanding multi-GPU builds
- 80 PLUS Gold certification reduces energy waste
- Full modular design keeps cables tidy
- Semi-passive fan stays off until 30 % load
- Compact 140 mm depth fits smaller cases
Specifications
| Brand | SeaSonic |
|---|---|
| Series | FOCUS GX |
| Model | FOCUS GX-850 (SSR-850FX) |
| Color | Black |
| Type | ATX12V / EPS12V |
| Maximum Power | 850 W |
| Fans | 1 |
| Modular | Full Modular |
| Energy-Efficient | 80 PLUS GOLD Certified |
Questions about this item
How do I install the Seasonic FOCUS GX-850 in my case and what step do builders often miss?
Mount the 140 mm deep ATX unit with four screws, connect the 24-pin ATX and EPS cables to the motherboard, then attach only the modular cables your build needs; the step often missed is firmly seating each modular plug into the PSU side until it clicks.
What maintenance or replacement will the Seasonic FOCUS GX-850 need over its lifetime?
The 120 mm fluid dynamic bearing fan is the only moving part; expect to clean dust from the intake every 6–12 months and replace the fan if bearing noise appears after many years — the unit carries a >100,000 hour MTBF rating.
What limit appears first when the Seasonic FOCUS GX-850 runs at high load for long periods?
The +12 V rail is rated for 70 A; sustained draws at that level will hit the current limit before the 850 W total rating, triggering over-current protection and shutting the unit down.
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