ESGAMING 400W Modular Flex ATX Alternatives: 6 Similar Picks Compared

How the alternatives compare

ESGAMING 500W Flex ATX Modular PSU

The ESGAMING 500W unit keeps the exact same 1U dimensions as the 400W model but adds 100W of output. You get the same 80 Plus Bronze efficiency and fully modular design in the identical 2.87 by 1.38 by 6.3-inch chassis. This extra power helps if your server or NAS components draw closer to the limit. If your current build runs near the 400W ceiling, this is the direct upgrade path. It offers no physical size penalty for the increased capacity. You retain the same intelligent fan control and protection circuits. This pick suits users who need headroom without changing their case layout or cable management setup.

FOSA 350W Fanless Mini ITX DC Power Supply

The FOSA 350W unit removes the cooling fan entirely, making it completely silent. It is also significantly thinner at 0.79 inches compared to the ESGAMING 1.38-inch height. You sacrifice active cooling for zero noise, which matters in quiet home offices or media centers. The lower 350W wattage limits high-power components. You lose the modular cable system, which may complicate cable management in tight spaces. This option works best if silence is your priority over expandability. It fits smaller chassis where even 1.38 inches is too tall. You trade efficiency certification details for absolute quiet operation and a slimmer profile.

ARESGAME 600W 80 Plus Bronze ATX Power Supply

The ARESGAME 600W unit switches to a standard ATX form factor, which is much larger than the 1U size. You gain 200W more power and a 5.5-inch width that fits standard cases. This is not for compact servers or NAS builds. You lose the space-saving advantage entirely. The unit is non-modular, so you manage more unused cables. It suits gamers or desktop users who need more power but do not care about 1U dimensions. The 80 Plus Bronze rating matches the original efficiency. You get more wattage for standard builds but sacrifice the compact footprint and modular flexibility of the ESGAMING unit.

ARESGAME AGV Series 650W Bronze PSU

The ARESGAME AGV 650W unit provides significantly more power at 650W but uses a standard ATX size. It is non-modular, which contrasts with the fully modular design of the ESGAMING unit. You get a five-year warranty, which is longer than typical 1U PSU offerings. The larger 5.5-inch width prevents it from fitting in 1U racks or small form factor cases. This pick is for standard mid-tower builds needing high wattage. You give up compactness and cable management ease for raw power and a longer warranty period. It suits users who prioritize longevity and output over space efficiency.

Thermaltake Smart BM3 650W Semi-Modular ATX 3.1 PSU

The Thermaltake Smart BM3 650W unit is semi-modular, meaning some cables are fixed. It supports ATX 3.1 standards, which helps with modern PCIe 5.0 GPUs. The standard ATX size is much larger than the 1U ESGAMING unit. You gain 250W more power and newer connector compatibility. The trade-off is the loss of compact form factor and full modularity. This unit fits standard mid-tower gaming PCs, not servers or NAS systems. You get a five-year warranty and higher output. It is a better choice for desktop builds needing PCIe 5.0 support rather than compact server applications.

ASRock Challenger 550W Bronze Power Supply

The ASRock Challenger 550W unit is a non-modular standard ATX power supply. It offers 150W more than the ESGAMING 400W unit but in a much larger 5.91-inch width. You lose the compact 1U profile and modular cable management. The 80 Plus Bronze efficiency rating is the same. This unit is designed for standard mid-tower cases, not small form factor builds. You get a five-year warranty, which is a notable advantage. It suits users who need more power for a standard desktop but do not require the space-saving benefits of a 1U PSU. It is a straightforward upgrade for non-compact systems.

Quick picks

Our 7 picks

1 Best overall

ESGAMING 400W Modular Flex ATX PSU

Best for: Compact 1U servers and NAS builds

Wattage

400W

Efficiency Rating

80 Plus Bronze

Modularity

Fully Modular

PCIe Connector Type

6+2 PCIE

Form Factor

Mini ITX

Dimensions

6.3 × 2.87 × 1.38 inches

View on Amazon: ESGAMING 400W Modular Flex ATX PSU Affiliate link

This ESGAMING unit is a 400W Flex ATX power supply designed for 1U rackmount servers, NAS systems, and small chassis builds. It carries an 80 Plus Bronze certification, delivering up to 85% energy efficiency to reduce power consumption and heat. The fully modular design allows for cleaner cable management inside compact cases. It includes comprehensive protection features like OVP and OCP to safeguard your components during 24/7 operation.

Pros

• 80 Plus Bronze efficiency rating for reliable long-term performance
• Fully modular cable system for easier management
• Compact 1U Flex ATX form factor fits small chassis
• Built-in OVP, OCP, OPP, and SCP protections

Cons

• Lower 400W wattage limits compatibility with high-power components
• No mention of fanless operation unlike some silent alternatives
• Standard Flex ATX size may not fit all Mini ITX cases

Good fit if

• You need a modular power supply for a 1U server or NAS
• You require 80 Plus Bronze efficiency for 24/7 operation
• You are building a compact system with low power demands

Skip if

• You need more than 400W of power for your build
• You require a non-modular unit for maximum simplicity
• You need a standard ATX form factor instead of Flex ATX

Verdict: ESGAMING 400W Flex ATX PSU is a practical choice for users building compact 1U systems like NAS or servers who need modular flexibility and energy efficiency. It suits low-power builds where space is tight and 24/7 reliability is key.

2 Also great

ESGAMING 500W Flex ATX Modular PSU

Best for: Compact 1U server and NAS builds

Wattage

500W

Efficiency Rating

80 PLUS Bronze

Modularity

Fully Modular

PCIe Connector Type

6+2 PCIE

Form Factor

Mini ITX

Dimensions

6.3 × 2.87 × 1.38 inches

View on Amazon: ESGAMING 500W Flex ATX Modular PSU Affiliate link

This 500W Flex ATX power supply offers 80 Plus Bronze efficiency and a fully modular design. It measures 6.3 x 2.87 x 1.38 inches, fitting 1U rackmounts and Mini ITX cases. The unit includes APFC for stable input voltage and intelligent fan control for quiet operation. You get comprehensive protections like OVP and OCP. It suits users needing compact, reliable power for NAS or server builds.

Pros

• 80 Plus Bronze efficiency rating
• Fully modular cable system
• Compact 1U Flex ATX form factor
• Built-in OVP, OCP, OPP, and SCP protections
• Intelligent temperature control fan

Cons

• Limited to 500W output
• Only two SATA connectors included
• Single 8-pin CPU power connector

Good fit if

• You need a compact PSU for a 1U rackmount server
• You require modular cables for clean builds in small chassis
• You want 80 Plus Bronze efficiency for lower heat

Skip if

• You need more than 500W of power
• You require a standard ATX form factor
• You need multiple PCIe power connectors for high-end GPUs

Verdict: ESGAMING 500W Flex ATX PSU provides efficient, modular power in a slim 1U package. It fits users building compact NAS or server systems who need reliable protection and clean cable management.

3 Also great

FOSA 350W Fanless Mini ITX DC Power Supply

Best for: silent small form factor builds

Wattage

350W

Form Factor

Mini ITX

Dimensions

6.06 × 1.38 × 0.79 inches

Weight

7.88 ounces

View on Amazon: FOSA 350W Fanless Mini ITX DC Power Supply Affiliate link

The FOSA 350W is a fanless Mini ITX DC power supply built for silent, compact PC builds. It delivers 350W of stable output with 85%+ efficiency. The unit measures just 1.38 by 0.79 by 6.06 inches and weighs 7.88 ounces. It includes overvoltage and short circuit protection. This PSU suits users who need zero noise and a small footprint in tight spaces.

Pros

• Fanless design for completely silent operation
• Ultra-compact Mini ITX form factor
• Built-in overvoltage and short circuit protection
• 85%+ efficiency rating for stable output

Cons

• Lower 350W wattage compared to 500W+ alternatives
• Non-modular fixed cable design
• Limited to Mini ITX DC input standard

Good fit if

• You need a completely silent PC build
• You have extremely tight space constraints
• You are building a low-power Mini ITX system

Skip if

• You require high wattage for gaming GPUs
• You need standard ATX 12V connectors
• You want modular cable management

Verdict: The FOSA 350W Fanless Mini ITX PSU is ideal for users prioritizing silence and compact size over raw power. It fits best in small form factor builds that do not demand high wattage.

4 Best budget

ARESGAME 600W 80 Plus Bronze ATX Power Supply

Best for: Standard ATX gaming builds

Wattage

600W

Efficiency Rating

80 PLUS Bronze

Fan Size

120mm

Dimensions

5.9 × 5.5 × 3.3 inches

Weight

3.43 pounds

View on Amazon: ARESGAME 600W 80 Plus Bronze ATX Power Supply Affiliate link

This ARESGAME unit delivers 600W of power with 80 PLUS Bronze efficiency. It features a 120mm fan for cooling and includes standard protections like OVP and SCP. The black cables offer a cleaner look inside your case. It suits users needing reliable mid-range power for standard ATX builds without the bulk of higher-wattage units.

Pros

• 600W output capacity
• 80 PLUS Bronze certified efficiency
• 120mm silent fan
• Standard protection circuits included

Cons

• Non-modular cable design
• Heavier build at 3.43 pounds
• Standard ATX form factor limits use in small cases

Good fit if

• You need 600W for a standard ATX build
• You prefer black cables for aesthetics
• You want standard protection features

Skip if

• You require a modular cable setup
• You are building in a small form factor case
• You need higher than 600W output

Verdict: ARESGAME 600W ATX Power Supply fits users who need reliable mid-range power for standard ATX builds. It offers solid efficiency and protection for typical gaming PCs.

5 Best premium

ARESGAME AGV Series 650W Bronze PSU

Best for: Standard gaming PCs needing 650W

Wattage

650W

Efficiency Rating

80 Plus Bronze

Modularity

Non Modular

Fan Size

120mm

Warranty

5 Year

Dimensions

5.9 × 5.5 × 3.3 inches

View on Amazon: ARESGAME AGV Series 650W Bronze PSU Affiliate link

The ARESGAME AGV 650W is a non-modular ATX power supply rated for 650W output. It carries 80 Plus Bronze certification for energy efficiency and includes a 120mm fan for cooling. The unit features heavy protection circuits including OVP, UVP, OPP, and SCP. It comes with a 5-year warranty. This unit suits gamers who need reliable stable output for their PC components without managing modular cables.

Pros

• 650W rated power output
• 80 Plus Bronze efficiency certification
• 120mm silent cooling fan
• 5-year warranty coverage
• Heavy protection circuits included

Cons

• Non-modular cable design
• Black cables only option
• Heavier build at 4.36 pounds

Good fit if

• You need 650W of stable power for gaming
• You prefer a standard ATX form factor
• You want a 5-year warranty

Skip if

• You require modular cables for clean builds
• You need higher than 650W wattage
• You prefer a fanless silent design

Verdict: The ARESGAME AGV 650W ATX PSU fits users who prioritize solid wattage and a five-year warranty over cable management flexibility.

6 Best semi-modular

Thermaltake Smart BM3 650W Semi-Modular ATX 3.1 PSU

Best for: Standard ATX builds with PCIe 5.0 GPUs

Wattage

650W

Efficiency Rating

80Plus Bronze

Modularity

Semi-Modular

ATX Version

ATX 3.1

Fan Size

120mm

Warranty

5 Year

View on Amazon: Thermaltake Smart BM3 650W Semi-Modular ATX 3.1 PSU Affiliate link

This 650W ATX 3.1 power supply features 80 Plus Bronze efficiency and PCIe Gen. 5 compliance. It uses a 120mm fan with Smart Zero Fan technology and Japanese 105°C capacitors. The semi-modular design helps manage cables in standard ATX cases. It suits builders needing reliable next-gen hardware support without full modularity costs.

Pros

• ATX 3.1 standard compatibility
• PCIe Gen. 5 compliant
• Semi-modular cable management
• 120mm Smart Zero Fan operation

Cons

• Semi-modular design leaves some cables attached
• Standard ATX size limits small case options
• Bronze efficiency is lower than Gold tiers

Good fit if

• You need PCIe Gen. 5 support for new GPUs
• You want semi-modular cable management
• You build in standard ATX cases

Skip if

• You require full modularity for clean builds
• You need Gold efficiency for lower heat
• You are building in a mini-ITX case

Verdict: Thermaltake Smart BM3 650W Semi-Modular fits users upgrading to PCIe 5.0 GPUs who prefer semi-modular cables. It offers solid ATX 3.1 compatibility for standard mid-tower builds.

7 Also great

ASRock Challenger 550W Bronze Power Supply

Best for: Standard mid-tower builds needing 550W

Wattage

550W

Efficiency Rating

80 PLUS Bronze

Modularity

Non-Modular

ATX Version

ATX 2.52

PCIe Connector Type

6+2-pin PCIe

Fan Size

120mm

View on Amazon: ASRock Challenger 550W Bronze Power Supply Affiliate link

The ASRock Challenger 550W is a standard ATX power supply designed for mid-range gaming and productivity builds. It delivers 550W of continuous power with 45.9A on the +12V rail. The unit holds 80 PLUS Bronze certification for up to 85% efficiency. It includes a 120mm fan and supports the ATX 2.52 standard. This non-modular unit fits standard mid-tower and full-tower cases.

Pros

• 550W continuous output with 45.9A on the +12V rail
• 80 PLUS Bronze certified for up to 85% efficiency
• 120mm Golf-Blade fan for optimized airflow and quiet operation
• 5V BOOST function stabilizes voltage during transient power spikes
• Includes 5-year warranty

Cons

• Non-modular design means unused cables remain inside the case
• Standard ATX size is too large for Flex ATX or 1U chassis
• Lacks digital display or monitoring software

Good fit if

• You need a reliable 550W unit for a standard ATX case
• You want 80 PLUS Bronze efficiency to reduce heat output
• You prefer a 5-year warranty for long-term peace of mind

Skip if

• You are building in a small form factor case requiring Flex ATX
• You need a modular cable setup for clean cable management
• You require more than 550W for high-end graphics cards

Verdict: ASRock Challenger 550W ATX PSU is a solid choice for users building in standard mid-tower cases who need dependable 80 PLUS Bronze efficiency and a 5-year warranty.

Specifications side by side

Frequently asked questions