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Compact silver 1U Flex PSU with 40 mm fan and modular cable sockets

Seasonic

Seasonic SSP-300SUG 300 W Flex 1U power supply

SKU CH-PXJE-C2SNJ MPN SSP-300SUG

A 300 W Flex 1U ATX12V supply with full modular cables, 80 PLUS Gold efficiency and a 40 mm double ball-bearing fan for compact chassis

  • Max wattage300 W
  • Power efficiency87%
  • Modular cablingFull Modular
  • Fan configuration40 mm Double ball Bearing fan
  • Power factor correctionActive
  • Main power connector24Pin
  • 80 PLUS Gold certification delivers 87 percent efficiency at typical loads
  • Full modular cabling lets you connect only the wires your build needs
  • Single +12 V rail rated at 25 A provides stable power for modern CPUs
  • 40 mm double ball-bearing fan runs quietly across the 0-50 °C operating range
  • MTBF exceeding 100000 hours signals long-term reliability for continuous operation

Compact 1U Power Supply

The Seasonic SSP-300SUG is a 300 W Flex ATX unit built for 1U rackmount chassis and small-form-factor workstations. It delivers a single +12 V rail rated at 25 A and carries 80 PLUS Gold certification at 87 % typical efficiency. Active PFC and DC-to-DC conversion keep voltage regulation tight across the 100-240 V input range.

Full Modular Build Quality

All cables detach from the housing so only the 24-pin, 4+4-pin, three SATA, one 4-pin Molex and one FDD leads you need stay inside the case. Japanese capacitors and a 40 mm double ball-bearing fan support an operating window of 0-50 °C and an MTBF beyond 100,000 hours. The 150 mm depth fits standard Flex bays without blocking adjacent slots.

Single +12 V Rail at 25 A

The entire 300 W budget sits on one +12 V rail, simplifying GPU or CPU power planning in dense builds. Over-voltage, over-power and short-circuit protection cover every output, while the 5 VSB line supplies 2 A for modern standby states. Haswell readiness confirms compatibility with low-power C-states.

How it compares

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

Price $80.99
Cheaper than about 75% of the 10,869 comparable items (median $142.99).
Max wattage 300 W
Lower than about 92% of the 930 comparable items (median 850 W).

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Specifications

Product
Brand nameSeaSonic
Model nameSSP-300SUG
Product typeATX12 V
Ports & slots
SATA power connectors3
Output type+3.3 V@10A, +5 V@14A, +12 V@25A, +5VSB@2A
Connection types1 x Main Power (24P)
1 x ATX12 V (4+4P)
3 x Peripherals: SATA
1 × 4P mole
1 x FDD
Power
Max wattage300 W
Power efficiency87%
Modular cablingFull Modular
Power factor correctionActive
Main power connector24Pin
12V railsSingle
Efficiency certification80 PLUS GOLD Certified
Overvoltage protectionYes
Supply voltage100–240 V
AC input frequency50/60 Hz
Size & build
Product dimensions1.59 in × 3.21 in × 5.91 in
Shipping weight0.92 kg
Package size159 × 102 × 3 mm
Compatibility
Haswell compatibilityReady
PSU length limit150 mm
More details
Fan configuration40 mm Double ball Bearing fan
Mean time between failures>100,000 h

Questions about this item

Will this 300 W unit fit my 1U rackmount chassis?

The power supply is a Flex 1U form factor with a maximum length of 150 mm, matching standard 1U server and slim desktop cases.

What CPU power connector does it include for modern motherboards?

It provides a 4+4-pin ATX12V cable that splits to serve both 4-pin and 8-pin CPU sockets.

How many SATA drives can I power directly from the modular cables?

Three SATA power connectors are supplied, so you can attach up to three SATA SSDs or hard drives without adapters.

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