ESGAMING 300W Flex ATX Power Alternatives: 6 Similar Picks Compared

Comparing Flex ATX Alternatives

SilverStone 500W Flex ATX Power Supply

The SilverStone 500W Flex ATX power supply delivers significantly more power than the ESGAMING 300W model. It reaches 500W while maintaining the same compact Flex ATX dimensions, measuring 3.21 by 1.59 by 5.91 inches. This unit carries an 80 Plus Gold efficiency rating, which reduces energy waste compared to the ESGAMING unit. You gain 200W of additional headroom for components that require more juice. The trade-off is a higher price point and potentially more heat output due to the increased power density. This option suits users who need more than 300W but cannot fit a standard ATX case. It is ideal for compact systems that need robust power without sacrificing efficiency.

Ptcliss 600W Fully Modular Flex ATX PSU

The Ptcliss 600W Flex ATX PSU offers the highest wattage in this comparison. It provides 600W of power in a similar form factor, measuring 3.2 by 1.58 by 6.5 inches. This unit is fully modular, allowing you to connect only the cables you need, which improves airflow in tight spaces. It also holds an 80 Plus Gold rating for better efficiency than the ESGAMING 300W. The main difference is the increased size and complexity. You get more power and cleaner cable management, but the unit is larger and more expensive. This pick is best for high-wattage small form factor builds where space is limited but power requirements are high. It sacrifices simplicity for performance and flexibility.

FSP FlexGURU 500W Flex ATX PSU

The FSP FlexGURU 500W Flex ATX PSU provides 500W of power in a compact chassis. It measures 1.59 by 3.21 by 5.91 inches and carries an 80 Plus Gold efficiency rating. This model offers 200W more power than the ESGAMING 300W unit while maintaining high efficiency. The FSP unit is designed for stable power delivery in tight spaces. It lacks the modularity of the Ptcliss but offers more power than the ESGAMING. You gain efficiency and power headroom, but you lose the lower cost and simpler design of the ESGAMING. This option suits users who need high efficiency and stable power in a tight space. It is a solid choice for SFF builds requiring more than 300W.

ESGAMING 300W TFX Power Supply

The ESGAMING 300W TFX Power Supply is nearly identical to the original Flex ATX model. It shares the same 300W wattage and dimensions, measuring 3.35 by 2.56 by 6.69 inches. Both units are designed for low-power NAS and mini ITX builds. The TFX version offers the same basic protections and power output. The main difference is the form factor compatibility with TFX slots. You get the same performance but in a slightly different physical profile. This option is best for low-power NAS and mini ITX builds that require a TFX form factor. It lacks the efficiency and power of higher-end alternatives. It is a direct alternative for users who prefer the TFX standard over Flex ATX.

SilverStone FX600z 600W Fully Modular Flex ATX

The SilverStone FX600z 600W Fully Modular Flex ATX PSU delivers 600W of power in a compact frame. It measures 3.4 by 1.6 by 6.5 inches and is fully modular. This unit offers double the power of the ESGAMING 300W model. The full modularity allows for better cable management in tight spaces. You gain significant power headroom and cleaner builds, but the unit is larger and more complex. The ESGAMING unit is simpler and smaller. This pick is best for compact systems needing high wattage and modularity. It suits users who require substantial power in a small chassis. It sacrifices simplicity and size for performance and cable management flexibility.

SilverStone 350W Gold Flex ATX PSU

The SilverStone 350W Gold Flex ATX PSU provides 350W of power, which is 50W more than the ESGAMING 300W. It measures 3.3 by 1.6 by 6 inches and carries an 80 Plus Gold efficiency rating. This unit offers better efficiency and slightly more power than the ESGAMING model. The SilverStone unit is designed for reliable power delivery in compact builds. You gain efficiency and a small power increase, but the unit is more expensive. The ESGAMING unit is simpler and cheaper. This option suits users who prioritize efficiency and stability over modular flexibility. It is not suitable for high-power multi-GPU setups. It is a solid choice for compact builds needing efficient power.

Quick picks

Our 7 picks

1 Best overall

ESGAMING 300W Flex ATX Power Supply

Best for: Compact NAS and mini ITX builds

Wattage

300W

Fan Size

80mm

Form Factor

Flex ATX

Dimensions

6.69 × 3.35 × 2.56 inches

View on Amazon: ESGAMING 300W Flex ATX Power Supply Affiliate link

This ESGAMING unit delivers 300W of power in a compact Flex ATX form factor, measuring 170 by 85 by 65 mm. It features an 80mm fan for forced air ventilation and includes comprehensive protections like OVP, UVP, and OCP. The 24-pin and 8-pin connectors split for flexibility. It suits NAS builds or mini ITX systems requiring a small, reliable power source with input voltage switching.

Pros

• 300W output capacity for low-power systems
• Compact 170x85x65mm Flex ATX dimensions
• Multiple safety protections including OVP and SCP
• Splittable 24-pin and 8-pin connectors

Cons

• Lower 300W wattage compared to 500W+ alternatives
• Non-modular cable design limits cable management
• 80mm fan may be louder than larger units

Good fit if

• You need a small power supply for a mini ITX build
• You are building a NAS with low power requirements
• You require multiple safety protections for your components

Skip if

• You need more than 300W of power
• You prefer fully modular cables for clean builds
• You require a larger 120mm fan for quieter operation

Verdict: ESGAMING 300W Flex ATX PSU fits users who need a compact, protected power source for low-wattage mini ITX or NAS builds. It does not suit high-power gaming rigs or those prioritizing silent operation.

2 Also great

SilverStone 500W Flex ATX Power Supply

Best for: compact systems needing 500W

Wattage

500W

Efficiency Rating

80 PLUS Gold

Form Factor

Flex ATX

Dimensions

5.91 × 3.21 × 1.59 inches

Weight

2.87 pounds

View on Amazon: SilverStone 500W Flex ATX Power Supply Affiliate link

This Silverstone unit delivers 500W of continuous power in a compact Flex ATX form factor. It holds 80 PLUS Gold certification for efficiency and uses Japanese primary capacitors for stability. The design features a single +12V rail and operates reliably up to 40°C. It suits users needing more headroom than 300W models while maintaining a small footprint for tight chassis spaces.

Pros

• 500W continuous power output
• 80 PLUS Gold efficiency certification
• Japanese primary capacitors
• Single +12V rail design
• Rated for 24/7 operation at 40°C

Cons

• Higher wattage may exceed needs for low-power builds
• Fixed output without modular cable management
• Heavier than 300W alternatives at 2.87 pounds

Good fit if

• You need 500W for a compact server or workstation
• You prioritize high efficiency in a small form factor
• You require reliable continuous operation at elevated temperatures

Skip if

• You only need 300W for basic office tasks
• You require fully modular cables for clean builds
• You are building a standard ATX desktop case

Verdict: Silverstone FX500-G 500W Flex ATX offers robust power density for compact systems. It fits users who need more than 300W but cannot fit standard ATX units.

3 Also great

Ptcliss 600W Fully Modular Flex ATX PSU

Best for: High-wattage small form factor builds

Wattage

600W

Efficiency Rating

80 Plus Gold

Modularity

Fully Modular

PCIe Connector Type

8-pin, 6-pin

Form Factor

Flex ATX

Dimensions

6.5 × 3.2 × 1.58 inches

View on Amazon: Ptcliss 600W Fully Modular Flex ATX PSU Affiliate link

This Ptcliss unit delivers 600W of power in a compact Flex ATX chassis. It carries an 80 Plus Gold efficiency rating, meaning it wastes less energy as heat. The fully modular design lets you connect only the cables you need. Japanese capacitors and DC-DC structure aim for stable output. It fits small form factor builds where space is tight but higher wattage is required.

Pros

• 600W output for high-performance small builds
• 80 Plus Gold efficiency rating
• Fully modular cable management
• Active PFC for wide voltage input

Cons

• Heavy at 1.55 pounds for its size
• No mention of cable length or connectors
• Limited availability compared to major brands

Good fit if

• You need 600W in a Flex ATX slot
• You want high efficiency in a small case
• You prefer fully modular cable routing

Skip if

• You require a standard ATX form factor
• You need a budget 300W unit
• You prioritize lightweight components over power

Verdict: Ptcliss 600W Flex ATX Gold offers strong wattage and efficiency for tight spaces. It suits builders who need reliable power in a small chassis without standard ATX dimensions.

4 Also great

FSP FlexGURU 500W Flex ATX PSU

Best for: High-efficiency SFF builds over 300W

Wattage

500W

Efficiency Rating

80 Plus Gold

Modularity

Non-Modular

Fan Size

40mm

Warranty

5-Year

Form Factor

Flex ATX

View on Amazon: FSP FlexGURU 500W Flex ATX PSU Affiliate link

The FSP FlexGURU Pro delivers 500W of power in a compact Flex ATX form factor. It earns 80 PLUS Gold efficiency, reducing heat and energy use. The unit uses a 40mm fan with intelligent speed control for thermal management. Japanese electrolytic capacitors ensure stable voltage regulation. Its all-black round cables simplify routing in small chassis. This PSU suits users needing reliable power for SFF builds or 1U systems.

Pros

• 500W output capacity for robust performance
• 80 PLUS Gold efficiency rating
• Japanese main electrolytic capacitors for reliability
• Intelligent 40mm fan speed control
• Flexible all-black round cabling

Cons

• 40mm fan size is smaller than standard PSUs
• Fixed non-modular cable design
• Higher price point than basic 300W units

Good fit if

• You need more than 300W in a Flex ATX chassis
• You prioritize high efficiency for heat reduction
• You are building a dense SFF or 1U system

Skip if

• You require full modular cabling for cable management
• You are limited to a 300W power budget
• You need a larger 120mm or 140mm fan

Verdict: FSP FlexGURU Pro 500W Flex ATX fits users who need high efficiency and stable power in a tight space. It is a solid choice for SFF builds requiring more than 300W.

5 Best budget

ESGAMING 300W TFX Power Supply

Best for: low-power NAS and mini ITX builds

Wattage

300W

Fan Size

80mm

Form Factor

Flex ATX

Dimensions

6.69 × 3.35 × 2.56 inches

View on Amazon: ESGAMING 300W TFX Power Supply Affiliate link

This ESGAMING unit provides 300W of power in a compact Flex ATX form factor, measuring 170 by 85 by 65 mm. It includes an 80mm fan for forced air ventilation and supports a 115/220V input switch. The design features comprehensive protections like OVP, UVP, and OCP. You should consider this if you need a reliable power source for NAS or mini ITX builds that fit into ultra-thin desktops or small enterprise servers.

Pros

• 300W output capacity
• Compact 170x85x65mm Flex ATX size
• Includes multiple safety protections
• Splittable 24-pin and 8-pin connectors

Cons

• Lower 300W wattage compared to 500W+ alternatives
• 80mm fan may produce more noise than larger fans
• No 80 Plus efficiency certification listed

Good fit if

• You need a low-power solution for a NAS
• You are building an ultra-thin mini ITX desktop
• You require a small form factor for enterprise use

Skip if

• You need high wattage for gaming GPUs
• You require 80 Plus Gold efficiency
• You want a fully modular cable setup

Verdict: ESGAMING 300W TFX Flex ATX PSU is a compact option for low-power systems like NAS or mini ITX builds. It fits well in tight spaces but lacks the efficiency and power of higher-end alternatives.

6 Best premium

SilverStone FX600z 600W Fully Modular Flex ATX

Best for: Compact systems needing high wattage and modularity

Wattage

600W

Efficiency Rating

Cybenetics Platinum

Modularity

Fully Modular

PCIe Connector Type

12V-2x6, PCIe 8-pin, 6-pin

Form Factor

Flex ATX

Dimensions

6.5 × 3.4 × 1.6 inches

View on Amazon: SilverStone FX600z 600W Fully Modular Flex ATX Affiliate link

This Silverstone unit delivers 600W of continuous power in a standard Flex ATX chassis. It features Cybenetics Platinum efficiency and includes a built-in 300W 12V-2x6 connector. The design uses Japanese primary capacitors for stable 24/7 operation. You get full modularity and support for PCIe 8-pin and 6-pin connections. This high-output option suits users needing significant power in a small form factor.

Pros

• 600W continuous power output rated for 50°C
• Cybenetics Platinum efficiency rating
• Fully modular cable design
• Includes built-in 300W 12V-2x6 connector
• Japanese primary capacitors for reliability

Cons

• Larger dimensions (6.5 inches long) than 300W competitors
• No 80 Plus certification listed, only Cybenetics
• Higher wattage may exceed needs for low-power builds

Good fit if

• You need 600W of power in a Flex ATX size
• You require a fully modular design for clean cable management
• You need native 12V-2x6 support for modern GPUs

Skip if

• You are limited to a 300W power budget
• You need a TFX form factor instead of Flex ATX
• You prefer a smaller footprint than 6.5 inches in length

Verdict: Silverstone FX600z 600W Flex ATX is a high-performance choice for compact systems requiring substantial power and modern connector support.

7

SilverStone 350W Gold Flex ATX PSU

Best for: Compact efficient builds under 350W

Wattage

350W

Efficiency Rating

80 Plus Gold

Modularity

Fixed Cables

PCIe Connector Type

PCIe 6pin

Form Factor

Flex ATX

Dimensions

6 × 3.3 × 1.6 inches

View on Amazon: SilverStone 350W Gold Flex ATX PSU Affiliate link

This Silverstone unit delivers 350W of continuous power in a compact Flex ATX chassis. It holds 80 PLUS Gold efficiency and runs reliably at 40°C. The fixed cables and single +12V rail simplify builds for small form factor PCs. You get PCIe 6-pin support and active PFC for stable performance. It suits users who need high efficiency in a tight space without the complexity of modular wiring.

Pros

• 80 PLUS Gold efficiency rating
• 350W continuous output at 40°C
• Single +12V rail design
• Active PFC support

Cons

• Fixed cables limit cable management flexibility
• Only one PCIe 6-pin connector
• Lower wattage than 500W alternatives

Good fit if

• You need high efficiency in a small chassis
• You are building a compact single-GPU system
• You prefer fixed cables for simplicity

Skip if

• You need to connect multiple high-power GPUs
• You want fully modular cable management
• You require more than 350W of power

Verdict: Silverstone FX350-G-VT 350W Flex ATX is a solid choice for compact builds needing efficient, reliable power. It fits users who prioritize efficiency and stability over modular flexibility. It is not suitable for high-power multi-GPU setups.

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Frequently asked questions