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Rectangular black ATX power supply unit with modular cable sockets and 135 mm fan grille

Seasonic

Seasonic Vertex GX-850 850 W power supply

SKU CH-KCM7-3DFPM MPN Vertex GX-850

An ATX 3.0 compatible, fully modular 850 W unit with a 16-pin Gen 5 PCIe cable, 135 mm FDB fan, Japanese 105 °C capacitors and Cybenetics A noise rating

  • Max wattage850 W
  • Modular cablingFull Modular
  • Fan configuration1 × 135 mm Fluid Dynamic Bearing (FDB) Fan
  • PCIe power connectors16-Pin Gen 5 PCIe Cable (12VHPWR)
  • PSU length limit160 mm
  • Efficiency certification80 PLUS GOLD Certified

Model ATX 3.0 Gold (850W)

  • ATX 3.0 and PCIe 5.0 ready for modern GPU builds
  • 80 PLUS Gold certification delivers high efficiency under load
  • Fully modular cabling keeps the interior clean and airflow unobstructed
  • 135 mm Fluid Dynamic Bearing fan with hybrid silent control runs quietly
  • Japanese 105 °C capacitors provide long-term reliability

850 W ATX 3.0 power supply

This 850 W unit follows the ATX 3.0 standard and includes a 16-pin 12VHPWR cable for PCIe 5.0 graphics cards. It is fully modular and uses a 135 mm fluid dynamic bearing fan with hybrid silent control. Japanese 105 °C capacitors and tight voltage regulation support stable delivery.

Suited for single-GPU builds, not multi-GPU

Builders assembling a high-performance system with one modern GPU will find the 850 W capacity and single 12VHPWR connector a direct match. The fully modular design keeps cable routing clean. Systems that require two or more 12VHPWR connections, or that need more than 850 W for extreme overclocking, should look at a higher-wattage or multi-connector unit.

One 12VHPWR cable included

The box provides a single 16-pin Gen 5 PCIe cable (12VHPWR) for the graphics card. If your GPU requires two such connectors, or if you plan to run dual cards each needing 12VHPWR, this unit cannot supply them natively.

How it compares

Measured against everything we stock in ATX Desktop Power Supplies, at today’s prices. Recalculated every night.

Price $159.99
Pricier than about 54% of the 10,869 comparable items (median $142.99).
Max wattage 850 W
Typical for this category: the median of 930 items is 850 W.

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Specifications

Product
Brand nameSeaSonic
Model nameVertex GX-850
Product typeATX / ATX 3.0 Compatible
Ports & slots
PCIe power connectors16-Pin Gen 5 PCIe Cable (12VHPWR)
Output typeAmple +12 V Output
Power
Max wattage850 W
Modular cablingFull Modular
Efficiency certification80 PLUS GOLD Certified
Size & build
Product dimensions6.3 in × 5.9 in × 3.4 in
Product weight4.34 lb (1.97 kg)
Shipping weight3.83 kg
Package size345 × 189 × 114 mm
Compatibility
PSU length limit160 mm
Environment & compliance
PSU noise ratingCybenetics A
More details
Fan configuration1 × 135 mm Fluid Dynamic Bearing (FDB) Fan

Other versions of this model

4 more in the same range

Questions about this item

What case clearance does the 160 mm length and 135 mm fan require?

The unit is 160 mm long and uses a single 135 mm Fluid Dynamic Bearing fan, so your chassis must provide at least that depth and vertical clearance above the PSU mounting area.

Which cables must be attached during installation, and which step is often missed?

Connect the 24-pin ATX, CPU 8-pin, and the 16-pin 12VHPWR cable for the GPU; the step most builders forget is fully seating the 12VHPWR connector until the latch clicks.

When should the 105 °C Japanese electrolytic capacitors be inspected or replaced?

These capacitors are rated for long life at 105 °C; under normal desktop use they typically last well beyond the 12-year warranty period, so no scheduled replacement is needed.

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