FOSA 350W Fanless Mini ITX Alternatives: 6 Similar Picks Compared
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The FOSA 350W Fanless Mini ITX DC Power Supply offers a quiet, compact solution for small form factor builds. You might look for fosa mini itx DC power alternatives if you need more wattage or a different form factor. This unit delivers 350W with an 85%+ efficiency rating. Its fanless design ensures silent operation, which is ideal for noise-sensitive environments. The dimensions are just 1.38 inches wide and 0.79 inches high, fitting snugly into tight spaces. It also includes overvoltage and short circuit protection to safeguard your components.
However, some users may require higher power output or modular cabling options. The alternatives selected here share key specifications with the original, such as Mini ITX compatibility or high efficiency ratings. For instance, you might prefer a 500W unit for more demanding hardware or a modular design for cleaner cable management. This list compares 6 similar picks based on their published specifications. We focus on wattage, size, efficiency, and protection features. These specs determine how well each power supply fits your specific case and build requirements. You can choose the option that best matches your technical needs without compromising on quality or compatibility.
How Each Alternative Compares
ESGAMING 500W Flex ATX Modular PSU
The ESGAMING 500W Flex ATX PSU provides significantly more power than the FOSA unit. It delivers 500W compared to the FOSA's 350W, making it suitable for higher-demand builds. This model measures 2.87 by 1.38 by 6.3 inches, which is larger than the FOSA's 1.38 by 0.79 by 6.06 inches. It carries an 80 Plus Bronze efficiency rating. You lose the fanless operation found in the FOSA, as this unit uses active cooling. It is ideal for NAS or server builds where space allows for a slightly larger unit and noise is less critical than raw wattage.
ESGAMING 400W Modular Flex ATX PSU
The ESGAMING 400W Modular Flex ATX PSU offers 400W of output, exceeding the FOSA's 350W capacity. It features modular cabling, which the FOSA does not list, allowing for cleaner cable management in tight spaces. The dimensions are 2.87 by 1.38 by 6.3 inches, making it physically larger than the compact FOSA unit. It holds an 80 Plus Bronze efficiency rating. Unlike the fanless FOSA, this unit relies on active cooling. It is a practical choice for users who need modular flexibility and slightly higher wattage in a compact form factor, accepting the trade-off of active noise for improved cable organization.
Rosewill 500W Fully Modular Mini ITX PSU
The Rosewill 500W Fully Modular Mini ITX PSU provides 500W of power, which is 150W more than the FOSA. It is fully modular, offering superior cable management compared to the FOSA's fixed cabling. The unit measures 3.15 by 1.57 by 6.5 inches, making it larger than the FOSA's 1.38 by 0.79 by 6.06 inches design. It includes active PFC and a five-year warranty. You give up the silent, fanless operation of the FOSA for this higher wattage and modularity. It is best for builders who prioritize modular flexibility and robust protection features over silent, ultra-compact operation.
FSP 220W Mini ITX PSU
The FSP 220W Mini ITX PSU offers lower wattage than the FOSA 350W unit, providing only 220W. It measures 1.6 by 3.2 by 5.9 inches, which is wider and taller than the FOSA's 1.38 by 0.79 by 6.06 inches footprint. It features active PFC for improved power factor correction. Unlike the fanless FOSA, this unit likely uses active cooling, though specific fan details are not listed. It is a compact option for low-power Mini ITX builds where 350W is unnecessary. You trade the higher wattage and fanless silence of the FOSA for a potentially smaller width, suitable for very tight low-power systems.
Thermaltake Smart 600W 80 Plus ATX PSU
The Thermaltake Smart 600W 80 Plus ATX PSU is a standard ATX unit, not a Mini ITX form factor. It delivers 600W, which is much higher than the FOSA's 350W. The dimensions are 4 by 7 by 8.9 inches, making it significantly larger than the compact FOSA unit. It includes active PFC and 80 Plus efficiency. You lose the compact size and fanless operation entirely. This unit is designed for standard ATX cases where space is not a constraint. It is suitable for users needing high wattage and standard compatibility, sacrificing the small form factor benefits of the FOSA for greater power output and standard sizing.
Apevia SFX 400W Power Supply
The Apevia SFX 400W Power Supply provides 400W of output, exceeding the FOSA's 350W capacity. It measures 4 by 2.5 by 5 inches, which is larger than the FOSA's 1.38 by 0.79 by 6.06 inches dimensions. It is a Mini ITX form factor unit. Unlike the fanless FOSA, this unit likely uses active cooling for thermal management. It offers solid basic specs for small cases. You trade the silent, ultra-compact design of the FOSA for higher wattage and a more standard small form factor size. It is suitable for users who need more power than 350W and can accommodate a slightly larger, actively cooled unit.
Quick picks
Our 7 picks
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
This FOSA unit delivers 350W of power in an ultra-compact Mini ITX form factor. It features a fanless design for silent operation, making it suitable for noise-sensitive environments. The unit includes overvoltage and short circuit protection to safeguard your components. With dimensions of 6.06 x 1.38 x 0.79 inches, it fits snugly in tight spaces. It operates efficiently at 85%+ and withstands temperatures from 0°C to 40°C.
Pros
- Fanless design ensures completely silent operation
- Compact Mini ITX form factor fits tight spaces
- Built-in overvoltage and short circuit protection
- 85%+ efficiency for stable power delivery
- Coated PCBA for enhanced durability
Cons
- Lower wattage than competitors on this list
- No active cooling for high thermal loads
- Limited temperature operating range of 40°C max
Good fit if
- You need a silent power supply for a home theater PC
- You are building a small form factor PC with low power needs
- You prioritize compact size over maximum wattage
Skip if
- You require more than 350W of power
- You need a modular cable setup
- You plan to run high-end gaming hardware
Verdict: FOSA 350W Fanless Mini ITX PSU is a quiet, compact option for low-power builds. It suits users who value silence and small dimensions over raw wattage.
ESGAMING 500W Flex ATX Modular PSU
Best for: High-power compact NAS and server 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
The ESGAMING 500W Flex ATX power supply delivers 500W of power in a compact 1U chassis. It features 80 PLUS Bronze certification for reliable efficiency and includes a fully modular design for cleaner cable management. The unit measures 6.3 by 2.87 by 1.38 inches and uses intelligent fan control for quiet operation. It suits users needing high wattage in a small form factor build.
Pros
- 500W output capacity for demanding mini builds
- Fully modular cable system for easy management
- 80 PLUS Bronze efficiency rating reduces heat
- Compact 1U Flex ATX dimensions fit small cases
- Built-in OVP, OCP, OPP, and SCP protections
Cons
- Includes a cooling fan unlike fanless alternatives
- Only 80 PLUS Bronze efficiency rating
- Heavier and bulkier than 350W fanless options
Good fit if
- You need 500W in a Flex ATX chassis
- You want fully modular cables for clean builds
- You require 80 PLUS Bronze efficiency certification
Skip if
- You require a completely fanless silent design
- You only need 350W or less power
- You want 80 PLUS Gold efficiency ratings
Verdict: The ESGAMING 500W Flex ATX PSU fits users who need high wattage and modularity in a small chassis. It is a practical choice for NAS or server builds where space is tight but power demands are high.
ESGAMING 400W Modular Flex ATX PSU
Best for: compact NAS and HTPC builds needing modularity
- 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 400W Flex ATX power supply offers 80 Plus Bronze efficiency, reaching up to 85% to reduce heat and power consumption. It features a fully modular design for cleaner cable management in compact Mini ITX builds. The unit includes intelligent temperature control for quiet operation and comprehensive protections like OVP and OCP. It is a solid choice for NAS, HTPC, or small chassis systems where space and reliability matter.
Pros
- 80 Plus Bronze certification for up to 85% energy efficiency
- Fully modular cable system for improved airflow and clean builds
- Built-in OVP, OCP, OPP, and SCP protections
- Intelligent temperature control for quiet fan operation
Cons
- 80 Plus Bronze rating is lower than the Gold and Platinum options on this list
- Includes a cooling fan, unlike the fanless FOSA alternative at the top
- Smaller 400W output compared to the 500W and 600W competitors
Good fit if
- You need a fully modular PSU for a compact Mini ITX or NAS build
- You want 80 Plus Bronze efficiency to reduce heat and power usage
- You require comprehensive protections like OVP and OCP for 24/7 operation
Skip if
- You require a completely fanless design for silent operation
- You need higher efficiency ratings like 80 Plus Gold or Platinum
- You require more than 400W of power for high-end components
Verdict: ESGAMING 400W Flex ATX PSU is a practical option for users building compact systems who prioritize modular cabling and solid efficiency. It fits well in NAS or HTPC cases where space is tight but some active cooling is acceptable.
Rosewill 500W Fully Modular Mini ITX PSU
Best for: Modular Mini ITX builds needing 500W
- Wattage
- 500W
- Modularity
- Fully Modular
- PCIe Connector Type
- 6+2 pin
- Fan Size
- 40mm
- Warranty
- 5-year
- Form Factor
- Mini ITX
View on Amazon: Rosewill 500W Fully Modular Mini ITX PSU Affiliate link
This Rosewill unit delivers 500W in a compact Mini ITX and Flex ATX form factor. It features a fully modular design, allowing you to connect only the cables you need. The 40mm fan includes intelligent thermal speed control to manage noise and heat. With full-range active PFC, it accepts 90-264V input, making it suitable for various power environments. It includes essential protections like OVP and OCP.
Pros
- 500W maximum power output
- Fully modular cable management
- 40mm fan with thermal control
- Full-range active PFC (90-264V)
- Comprehensive protection circuits
Cons
- 40mm fan size may limit airflow in tight cases
- Only two SATA connectors included
- Heavier build at 1.43 pounds
Good fit if
- You need a fully modular PSU for a Mini ITX build
- You require 500W of power in a small form factor
- You want intelligent fan speed control for quieter operation
Skip if
- You need a fanless design for absolute silence
- You require more than two SATA connectors
- You prefer a larger fan for better cooling efficiency
Verdict: Rosewill VIT 500W Mini ITX PSU is a solid choice for builders needing high wattage in a small case. It fits users who prioritize modular cable management and reliable protection features over fanless operation.
FSP 220W Mini ITX PSU
Best for: Low-power Mini ITX builds
- Wattage
- 220W
- Efficiency Rating
- 80 Plus Certified
- Fan Size
- 40mm
- Form Factor
- Mini ITX
- Power Factor Correction
- Active PFC
- Dimensions
- 5.9 × 1.6 × 3.2 inches
View on Amazon: FSP 220W Mini ITX PSU Affiliate link
This FSP unit delivers 220 watts of continuous power in a compact Mini ITX form factor. It features Active PFC for stable voltage handling and an 80 Plus certification for efficiency. The 40mm fan links to thermal controls, keeping noise low while cooling components. At 1.8 pounds, it is lightweight. You should choose this if you need a small, efficient power source for low-power builds.
Pros
- 220-watt continuous output
- 80 Plus certification
- Active PFC support
- Compact 1.6 x 3.2 x 5.9 inch size
Cons
- Low 220W output limits high-end components
- Includes a 40mm fan, not fanless
- No modular cable options listed
Good fit if
- You need a small form factor power supply
- You are building a low-power system
- You want 80 Plus efficiency
Skip if
- You require more than 220 watts
- You need a fanless design
- You want fully modular cables
Verdict: FSP 220W Mini ITX PSU is a compact, efficient choice for low-power Mini ITX builds. It fits users who prioritize size and efficiency over raw wattage.
Thermaltake Smart 600W 80 Plus ATX PSU
Best for: Standard ATX cases needing 600W
- Wattage
- 600W
- Efficiency Rating
- 80 PLUS Certified
- PCIe Connector Type
- 6 plus 2pin
- Warranty
- 5 Year
- Form Factor
- ATX
- Power Factor Correction
- Active PFC
View on Amazon: Thermaltake Smart 600W 80 Plus ATX PSU Affiliate link
This Thermaltake unit delivers 600W continuous output at 40°C, meeting Intel ATX 12V 2.31 and EPS 12V 2.92 standards. It features 80 PLUS certification for 80% efficiency and includes active power factor correction. The design supports two PCIe 6+2 pin connectors and offers industry-grade protections like over-power and short-circuit safeguards. It is built for standard ATX cases requiring reliable, high-wattage power delivery.
Pros
- 600W continuous output at 40°C
- 80 PLUS Certified efficiency
- Active PFC for power factor correction
- Supports two PCIe 6+2 pin connectors
- 100,000-hour MTBF rating
Cons
- Standard ATX size limits use in Mini ITX builds
- Single 80 PLUS rating lacks Gold efficiency
- Non-modular cable management
Good fit if
- You need 600W for a standard ATX case
- You require active PFC for stable voltage
- You want 80 PLUS certified efficiency
Skip if
- You are building a Mini ITX system
- You need Gold efficiency for lower heat
- You require modular cables for clean builds
Verdict: Thermaltake SMART 600W ATX Power Supply fits users needing reliable 600W output for standard ATX cases. It provides solid efficiency and protections but lacks the compact form factor or modular flexibility needed for small builds.
Apevia SFX 400W Power Supply
Best for: Compact Mini ITX builds
- Wattage
- 400W
- PCIe Connector Type
- 6/8pin PCIe
- Fan Size
- 80mm
- Form Factor
- Mini ITX
- Dimensions
- 5 × 4 × 2.5 inches
- Weight
- 2.03 pounds
View on Amazon: Apevia SFX 400W Power Supply Affiliate link
This Apevia unit delivers 400W in a compact Mini ITX form factor. It features an 80mm fan that activates based on thermal sensors, keeping noise low during light loads. The build includes sleeved cables and standard connectors like a 20+4pin main, PCIe, and SATA. It fits small builds where space is tight but you need reliable power delivery for modest components.
Pros
- 400W total output capacity
- 80mm thermal sensing fan
- Sleeved cables included
- Compact 125x100x63.5mm dimensions
Cons
- Fan is not fully fanless
- Limited connector count for high-end builds
- No 80 Plus efficiency rating listed
Good fit if
- You need a Mini ITX power supply
- You prefer sleeved cables for aesthetics
- Your build requires under 400W
Skip if
- You require a fanless design
- You need high-end efficiency ratings
- You require modular cabling
Verdict: Apevia 400W Mini ITX PSU offers solid basic specs for small cases. It suits users prioritizing compact size and cable management over high efficiency or fanless operation.
Specifications side by side
| Spec | FOSA 350W Fanless Mini ITX DC Power Supply | ESGAMING 500W Flex ATX Modular PSU | ESGAMING 400W Modular Flex ATX PSU | Rosewill 500W Fully Modular Mini ITX PSU | FSP 220W Mini ITX PSU | Thermaltake Smart 600W 80 Plus ATX PSU | Apevia SFX 400W Power Supply |
|---|---|---|---|---|---|---|---|
| Wattage | 350W | 500W | 400W | 500W | 220W | 600W | 400W |
| Efficiency Rating | not stated | 80 PLUS Bronze | 80 Plus Bronze | not stated | 80 Plus Certified | 80 PLUS Certified | not stated |
| Modularity | not stated | Fully Modular | Fully Modular | Fully Modular | not stated | not stated | not stated |
| PCIe Connector Type | not stated | 6+2 PCIE | 6+2 PCIE | 6+2 pin | not stated | 6 plus 2pin | 6/8pin PCIe |
| Fan Size | not stated | not stated | not stated | 40mm | 40mm | not stated | 80mm |
| Warranty | not stated | not stated | not stated | 5-year | not stated | 5 Year | not stated |
| Form Factor | Mini ITX | Mini ITX | Mini ITX | Mini ITX | Mini ITX | ATX | Mini ITX |
| Power Factor Correction | not stated | not stated | not stated | Active PFC | Active PFC | Active PFC | not stated |
| Size | not stated | 500W | not stated | Mini ITX/Flex ATX | not stated | 600W | not stated |
| Device Compatibility | not stated | not stated | not stated | NAS | not stated | not stated | not stated |
| Dimensions | 6.06 × 1.38 × 0.79 inches | 6.3 × 2.87 × 1.38 inches | 6.3 × 2.87 × 1.38 inches | 6.5 × 3.15 × 1.57 inches | 5.9 × 1.6 × 3.2 inches | 8.9 × 4 × 7 inches | 5 × 4 × 2.5 inches |
| Weight | 7.88 ounces | not stated | not stated | 1.43 pounds | 1.8 pounds | 4.5 pounds | 2.03 pounds |
| Color | default | not stated | not stated | Black | not stated | Black | not stated |
| Model | not stated | 1U500W | 1U400W | VIT500 | FSP220-60LE(80) | PS-SPD-0600NPCWUS-W | SFX-AP400W |
You can evaluate supermicro mini itx ddr4 motherboard alternatives to compare connector placement and socket power requirements.
Frequently asked questions
Is the FOSA 350W truly fanless?
Yes, the FOSA 350W Fanless Mini ITX DC Power Supply operates without a fan. This design ensures silent performance, making it ideal for users who prioritize quiet operation in small form factor builds. It measures 1.38 by 0.79 by 6.06 inches and weighs 7.88 ounces.
Which alternative offers the most wattage?
The ESGAMING 500W Flex ATX PSU offers the highest wattage at 500W. It also features 80 Plus Bronze efficiency. This model measures 2.87 by 1.38 by 6.3 inches. It is a practical choice for NAS or server builds where space is tight but power demands are high.
Are there modular options in this list?
Yes, both the ESGAMING 500W and 400W models are modular. The Rosewill 500W is fully modular as well. Modular designs allow you to connect only the cables you need, which helps with cable management in compact cases. The Rosewill unit also includes Active PFC.
What is the smallest form factor available?
The FOSA 350W and ESGAMING models use Mini ITX or Flex ATX form factors. These are designed for compact chassis. The FOSA unit is particularly small, measuring just 1.38 inches wide. The ESGAMING units are slightly wider at 2.87 inches but still fit small builds.
Can I use a standard ATX PSU instead?
You can use a standard ATX PSU if your case supports it. The Thermaltake Smart 600W is a standard ATX unit. It measures 4 by 7 by 8.9 inches. However, it lacks the compact form factor needed for Mini ITX cases, so check your case dimensions first.
Does the FSP 220W have Active PFC?
Yes, the FSP 220W Mini ITX PSU includes Active PFC. This feature helps improve power efficiency and reduces strain on the electrical grid. It is a compact option weighing 1.8 pounds. It measures 1.6 by 3.2 by 5.9 inches, fitting low-power Mini ITX builds.
Which unit is best for NAS builds?
The ESGAMING 500W is rated for high-power compact NAS builds. The Rosewill 500W is also explicitly compatible with NAS devices. Both offer high wattage and modularity. The ESGAMING model provides 80 Plus Bronze efficiency, while the Rosewill offers a longer warranty period for reliability.
Is the Apevia 400W fanless?
No, the Apevia 400W is not fanless. It uses active cooling. It is designed for compact Mini ITX builds but prioritizes size and cable management over silent operation. It measures 4 by 2.5 by 5 inches and weighs 2.03 pounds. Choose it if you do not mind a fan.