We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Rectangular ATX power supply in matte black finish with fixed cables and a 120 mm fan grille

Seasonic

Seasonic S12III-550GB 550W 80+ Bronze power supply

SKU CH-FWJ4-YEQ72 MPN S12III-550GB

Delivers 550 W of 80 PLUS Bronze certified power with a single +12 V rail, two 6+2-pin PCIe connectors, six SATA connectors, a 120 mm sleeve-bearing fan under smart silent control, active PFC.

  • TypeIntel ATX 12 V
  • Maximum Power550 W
  • Fans120mm Sleeve Bearing fan
  • PFCActive
  • Main Connector20+4Pin
  • +12V RailsSingle

Options ATX 80+ Bronze (550W)

  • Delivers 550 W continuous power for stable system operation
  • 80 PLUS Bronze certification reaches 85 % efficiency at 50 % load
  • Single +12 V rail with 45 A simplifies high-demand GPU builds
  • 120 mm fan with S2FC adjusts speed for quiet cooling
  • Japanese capacitors rated at 105 °C ensure long-term reliability

Power for mainstream and gaming builds

This Seasonic S12III Bronze Series unit delivers 550 W of continuous power for a mainstream system or gaming rig. It meets the 80 PLUS Bronze standard with 82% efficiency at 20% and 100% load and 85% at 50% load. A single +12 V rail simplifies power distribution to the CPU and graphics card. Japanese capacitors rated at 105 °C support long-term reliability.

Fixed cables and a 140 mm depth

The non-modular design provides every cable needed for a standard PC, including a 20+4-pin main connector, two 6+2-pin PCI-Express connectors and six SATA power connectors. At 140 mm long the unit fits most ATX cases, but verify clearance before ordering. The 120 mm sleeve bearing fan is regulated by Seasonic S2FC fan control to balance noise and cooling.

550 W on a single +12 V rail

The single +12 V rail design delivers the full 550 W to CPU and GPU without multi-rail balancing. Active PFC accepts 110-240 V input at 50/60 Hz for worldwide use. Protection circuits include OPP, OVP, UVP and SCP to safeguard components. MTBF exceeds 100,000 hours.

Highlights

  • Delivers 550 W continuous power for stable system operation
  • 80 PLUS Bronze certification reaches 85 % efficiency at 50 % load
  • Single +12 V rail with 45 A simplifies high-demand GPU builds
  • 120 mm fan with S2FC adjusts speed for quiet cooling
  • Japanese capacitors rated at 105 °C ensure long-term reliability

Specifications

BrandSeaSonic
SeriesS12III Bronze Series
ModelS12III-550GB (SSR-550GB3)
TypeIntel ATX 12 V
Maximum Power550 W
Fans120mm Sleeve Bearing fan
PFCActive
Main Connector20+4Pin
+12V RailsSingle
PCI-Express Connector2 x 6+2-Pin
SATA Power Connector6
Max PSU Length140 mm
ModularNon-Modular
Energy-Efficient80 PLUS BRONZE Certified
Over Voltage ProtectionYes
Input Voltage110 - 240 V
Input Frequency Range50/60 Hz
Input Current8 - 4 A
Output+3.3V@20A, +5V@20A, [email protected] , [email protected] , [email protected]
MTBF>100,000 Hours
ApprovalsSafety and EMC: cTUVus, TUV, Gost-R, UkrTEST, CB, BSMI, Semko, CCC, CE, FCC, C-tick
Environmental Compliance: Energy Star, RoHS, WEEE, REACH
Connectors1 x Main Power (24/20 pins)
1 x CPU (8/4 pins)
2 x PCIe (8/6 pins)
6 x SATA
3 x Peripheral
1 x Floppy
Features80 PLUS Bronze Certified High Efficiency
Highly Reliable 105 °C Japanese Brand Capacitor
Ample + 12 V Outputs
Active Power Factor Correction (99 % PF Typical)
LLC resonant converter design
Smart & Silent Fan Control (S2FC)
120 mm Fluid Dynamic Bearing (FDB) Fans
Soft-Mount Rubber Cushions
Unique Easy Swap Connector
Universal AC Input (Full Range)
Ultra Ventilation (Honeycomb Structure)
Dimensions3.39" x 5.51" x 5.91"
Shipping weight2.16 kg
Package size267 × 201 × 99 mm

Other versions of this model

1 more in the same range

Same family, different memory, cooler or clock — compare before you commit.

Questions about this item

Will this unit fit in a standard ATX case with limited depth?

The chassis is 140 mm long, which matches the typical ATX power-supply clearance in most mid-tower cases.

Can it power a modern graphics card that needs two PCIe power plugs?

It includes two 6+2-pin PCIe connectors, so a card requiring up to two 8-pin plugs can be connected directly.

What efficiency can I expect at typical gaming loads?

The 80 PLUS Bronze rating guarantees 85 % efficiency at 50 % load and 82 % at both 20 % and 100 % load.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.