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Rectangular ATX power supply, matte black finish, modular cable sockets, 135 mm fan grille

Seasonic

Seasonic PRIME PX-850 850W 80 PLUS Platinum power supply

SKU CH-QK6Z-24QW3 MPN PRIME PX-850

Full-modular 850 W ATX unit with 80 PLUS Platinum efficiency, a 135 mm fluid-dynamic fan offering fanless operation, and micro-tolerance load regulation under 0.5 %

  • Max wattage850 W
  • Modular cablingFull Modular
  • Fan configuration1 × 135 mm Fluid Dynamic Bearing Fan
  • Main power connector20+4Pin
  • 12V railsSingle
  • PCIe power connectors6 × 6+2-Pin

Model ATX 80+ Platinum (850W) Black

  • 80 PLUS Platinum certification wastes less energy during conversion
  • Fully modular cabling lets you use only the cables you need
  • Premium hybrid fan control offers silent fanless operation
  • Micro tolerance load regulation under .5% delivers stable power
  • 150000 hours MTBF at 25°C indicates long-term reliability

850 W ATX power supply for high-performance builds

This fully modular ATX12V unit delivers 850 W of continuous power with 80 PLUS Platinum efficiency. A single +12 V rail rated at 70 A supplies clean current to demanding components. Load regulation stays under 0.5 % for stable voltage under heavy loads.

Ideal for multi-GPU systems needing six PCIe

Six 6+2-pin PCIe cables and ten SATA power connectors support multiple graphics cards and storage arrays. The 170 mm length fits most mid-tower and larger cases. Builds requiring only a few drives or a single GPU can use a smaller, less expensive unit.

Fanless mode via premium hybrid fan control

A 135 mm fluid dynamic bearing fan stops completely at low load when S3FC mode is selected. The rear switch toggles between fanless and constant cooling profiles without software. Silence-focused builders gain true zero-fan operation; noise-tolerant users may prefer a simpler design.

How it compares

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

Price $161.99
Pricier than about 55% 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
Product linePRIME Ultra Platinum
Model namePRIME PX-850 (SSR-850PD)
Product typeATX12 V
Ports & slots
PCIe power connectors6 × 6+2-Pin
SATA power connectors10
Output type+3.3 V@20A, +5 V@20A, +12 V@70A
Connection types1 x Main Power (24/20 pins)
2 x CPU (8/4 pins)
6 x PCIe (8/6 pins)
10 x SATA
5 x Peripheral
1 x Floppy
Power
Max wattage850 W
Modular cablingFull Modular
Main power connector20+4Pin
12V railsSingle
Efficiency certification80 PLUS PLATINUM Certified
Overvoltage protectionYes
Supply voltage100–240 V
AC input frequency50/60 Hz
Rated input current11–5.5 A
Size & build
Product dimensions3.39 in × 5.91 in × 6.69 in
Shipping weight3.61 kg
Package size343 × 206 × 140 mm
Compatibility
PSU length limit170 mm
Environment & compliance
Regulatory approvalscTUVus, TUV, CB, CCC, BSMI, EAC, CE, Energy Star, RoHS, WEEE, ErP Lot 6, REACH
More details
Fan configuration1 × 135 mm Fluid Dynamic Bearing Fan
Mean time between failures150,000 h MTBF @ 25 degree C, excl. fan

Other versions of this model

3 more in the same range

Questions about this item

How do I install the PRIME PX-850 and what step is often missed?

Mount the 170 mm ATX unit, connect the 20+4 pin main cable plus the two CPU 8/4 pin cables, then plug only the modular leads you need; the step people skip is pressing the fan-control button to choose S2FC or S3FC before first power-on.

What maintenance or replacement will the PRIME PX-850 need later?

The 135 mm fluid-dynamic-bearing fan is the only moving part; after many years it can be swapped for another 135 mm unit, while the rest of the supply is rated for 150000 hours MTBF at 25 °C excluding the fan.

What limit appears first under sustained heavy load on the PRIME PX-850?

The single +12 V rail delivers up to 70 A; if the combined GPU and CPU draw exceeds that current the over-current protection will trip before the 850 W total rating is reached.

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