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TOPOWER

TOPOWER TOP-FLEX-300W 300W Flex ATX Power Supply

SKU CH-9CS0-0ZF81 MPN TOP-FLEX-300W

A compact 300 W Flex ATX unit with active PFC, 80 PLUS certification and a 40 mm fan for small-form-factor builds

  • Max wattage300 W
  • Power efficiency> 80%
  • Modular cablingNon-Modular
  • Fan configuration1 × 40 mm fan
  • Power factor correctionActive
  • Main power connector20+4Pin
  • 300 W output powers compact builds
  • 80 PLUS certified efficiency above 80 % at typical loads
  • Active PFC corrects power factor across 100-240 V input
  • Dual +12 V rails each deliver 16 A for stable GPU power
  • 150 mm length fits slim Flex ATX chassis

300 W Flex ATX Power Supply

The Topower Top-Flex-300W delivers 300 W of continuous power in a compact Flex ATX form factor. It targets builders of small-form-factor desktops, HTPCs or industrial chassis that require an ATX-compliant unit shorter than standard PSUs. The 150 mm length fits tight layouts where full-size units cannot. Active PFC and a wide 100-240 V input suit global mains conditions.

Included Connectors and Their Impact

A fixed cable set provides one 20+4-pin main connector, one ATX 4-pin CPU connector, one PCI-E 6-pin graphics connector, three SATA power connectors, two peripheral connectors and one floppy connector. The single 6-pin PCI-E cable supports entry-level discrete graphics cards without adapters. Three SATA plugs handle multiple SSDs or hard drives. Non-modular wiring means every cable remains inside the case, so builders must route unused leads carefully.

Installation Notes and Common Issues

The unit mounts with standard ATX screw holes and measures 150 mm long, 80 mm wide and 40 mm high. A single 40 mm fan uses a push-pull airflow design; verify that the chassis vents align with the fan exhaust to avoid recirculation. Fixed cables add bulk behind the motherboard tray, so check clearance before closing the side panel. The 80 PLUS certified efficiency rating exceeds 80 percent from 20 to 100 percent load, reducing heat output in typical workloads.

How it compares

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

Price $59.99
Cheaper than about 85% 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 nameTOPOWER
Product lineFlex ATX Series
Model nameTOP-FLEX-300 W
Product typeATX
Ports & slots
PCIe power connectors1 × 6-Pin
SATA power connectors3
Output type+3.3 V@26A, +5 V@16A, +12V1@16A, +12V2@16A
Connection types1 x Main connector (20+4Pin)
1 x ATX 4 Pin
2 x Peripheral
3 x SATA
1 x Floppy
1 x PCI-E
Power
Max wattage300 W
Power efficiency> 80%
Modular cablingNon-Modular
Power factor correctionActive
Main power connector20+4Pin
12V rails2
Efficiency certification80 PLUS Certified
Supply voltage100–240 V
AC input frequency47–63 Hz
Rated input current4–2 A
Rated power300 W
Size & build
Product dimensions150 × 80 × 40 mm
Shipping weight1.18 kg
Package size222 × 165 × 64 mm
Compatibility
PSU length limit150 mm
More details
Fan configuration1 × 40 mm fan

Questions about this item

Will this 300 W unit fit inside a slim Flex-ATX case?

The power supply measures 150 mm long, 80 mm wide and 40 mm high, matching the standard Flex-ATX footprint used in most compact chassis.

Can it power a graphics card that needs a 6-pin PCIe connector?

Yes, the unit includes one 6-pin PCI-Express connector and two +12 V rails each rated at 16 A, providing up to 300 W total.

What motherboard power cables are supplied?

The non-modular cable set includes a 20+4 pin main connector, a 4-pin ATX 12 V connector, two peripheral connectors, three SATA connectors and one floppy connector.

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