Best FSP PC Power Supplies: 4 Models Compared

Quick picks

Our 4 picks

1 Best overall

FSP 400W Gold Flex ATX Mini ITX Power Supply

Best for: Compact Mini ITX systems with modest power needs

Wattage

400W

Efficiency Rating

80 Plus Gold

PCIe Connector Type

6+2 pin

Fan Size

4 cm

Form Factor

Mini ITX

Dimensions

5.9 × 1.6 × 3.25 inches

View on Amazon: FSP 400W Gold Flex ATX Mini ITX Power Supply Affiliate link

This FSP Flex ATX unit delivers 400W of power with 80 Plus Gold efficiency. Its 4 cm fan ensures quiet operation while keeping noise levels low. The compact 1.6-inch height fits small cases. It includes one PCIe connector for graphics cards. This model suits users needing reliable power in tight spaces without excess bulk.

Pros

• 80 Plus Gold certification for over 90% efficiency
• Compact 1.6-inch height for Mini ITX builds
• 4 cm fan provides low noise operation
• Includes 1x PCIe 6+2 pin connector

Cons

• 400W wattage limits high-end GPU support
• 4 cm fan size restricts airflow capacity
• Single PCIe connector limits multi-GPU setups

Good fit if

• You need a compact power supply for a Mini ITX case
• You prioritize energy efficiency with 80 Plus Gold certification
• You require quiet operation from a small form factor system

Skip if

• You need more than 400W of power
• You require multiple PCIe connectors for high-end GPUs
• You prefer larger fans for maximum airflow

Verdict: FSP 400W Mini ITX Gold PSU is ideal for small builds requiring efficient, quiet power. It fits users with modest GPU needs who value compact dimensions.

2 Best budget

FSP SFX Pro 450W Bronze Power Supply

Best for: small form factor office PCs

Wattage

450W

Efficiency Rating

80 Plus Bronze

Modularity

Non-Modular

Form Factor

Mini ITX

Device Compatibility

PCs

Dimensions

5 × 4 × 2.5 inches

View on Amazon: FSP SFX Pro 450W Bronze Power Supply Affiliate link

The FSP SFX Pro 450W is a compact power supply designed for small form factor builds. It features 80 PLUS Bronze efficiency and a DC-to-DC module design for stable voltage regulation. The unit includes an intelligent sleeve fan and flat black ribbon cables. It also comes with an SFX-to-ATX adapter bracket, allowing installation in standard ATX cases. This model suits budget-conscious builders needing reliable power in a small package.

Pros

• 80 PLUS Bronze efficiency rating
• DC-to-DC module design for stable voltage
• Includes SFX-to-ATX adapter bracket
• Intelligent sleeve fan for temperature control
• Flat black ribbon cables for tidy builds

Cons

• Lower 80 PLUS Bronze efficiency compared to Gold or Titanium options in this guide
• 450W output is insufficient for high-end gaming rigs
• Heavier at 2.69 pounds than typical SFX units

Good fit if

• You are building a small form factor PC
• You need an SFX-to-ATX adapter for larger cases
• You prioritize budget efficiency over peak performance

Skip if

• You require 80 PLUS Gold or Titanium efficiency
• You need more than 450W of power
• You are building a high-end gaming workstation

Verdict: FSP SFX Pro 450W Bronze PSU is a practical choice for small builds needing standard ATX compatibility and reliable daily office performance. It fits users who value compact dimensions and included adapter brackets over high-wattage gaming capabilities.

3 Best flex atx

FSP FlexGURU 500W Flex ATX PSU

Best for: small form factor builds needing Gold efficiency

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 500W is a Flex ATX power supply designed for small form factor builds. It carries an 80 Plus Gold efficiency rating, reaching up to 90% efficiency. The unit measures 1.59 by 3.21 by 5.91 inches and weighs 2.18 pounds. It includes a 40mm fan and Japanese capacitors. This PSU suits users needing reliable power for SFF cases, 1U systems, or networking gear.

Pros

• 80 Plus Gold efficiency for reduced heat and energy use
• Compact Flex ATX form factor fits small chassis
• Japanese electrolytic capacitors for stable voltage regulation
• Includes universal mounting bracket for easy installation

Cons

• 40mm fan size is smaller than standard PSUs
• 500W output is lower than full-size ATX options
• Round cables may be less flexible than flat designs

Good fit if

• You are building a small form factor PC
• You need a Gold efficiency rating for SFF builds
• You are installing 1U IPCs or networking gear

Skip if

• You require a standard ATX form factor
• You need more than 500W of power
• You prefer a larger 120mm or 140mm fan

Verdict: FSP FlexGURU Pro 500W Flex ATX is a compact, efficient choice for small form factor builds. It fits users who need Gold efficiency in a tight space for SFF cases or 1U systems.

4 Best premium

FSP Hydro Ti Pro 1000W Titanium ATX 3.1 PSU

Best for: High-end ATX 3.1 builds

Wattage

1000W

Efficiency Rating

80 PLUS Titanium, Cybenetics Titanium

Modularity

Fully Modular

ATX Version

ATX 3.1

PCIe Connector Type

12V-2x6, 6+2 pin

Fan Size

135mm

View on Amazon: FSP Hydro Ti Pro 1000W Titanium ATX 3.1 PSU Affiliate link

This FSP unit delivers 1000W of power with ATX 3.1 support. It holds both 80 PLUS and Cybenetics Titanium certifications for high efficiency. The 135mm fan features a zero-RPM mode for quiet operation. Its 150mm length fits smaller cases. You should choose this if you need top-tier efficiency and future-proof PCIe 5.1 compatibility for high-end builds.

Pros

• Dual Titanium efficiency certification for minimal power loss
• ATX 3.1 and PCIe 5.1 ready for next-gen hardware
• 135mm fan with zero-RPM mode for silent operation
• Compact 150mm length for high power density

Cons

• 1000W capacity exceeds needs for basic office PCs
• Fully modular design requires manual cable management
• Premium Titanium rating targets enthusiasts, not budget users

Good fit if

• You are building a high-end gaming PC with an ATX 3.1 case
• You prioritize ultra-quiet operation and high efficiency
• You need PCIe 5.1 support for future GPU upgrades

Skip if

• You are building a basic office computer with low power needs
• You require a pre-assembled non-modular solution
• You are on a tight budget and need Bronze efficiency

Verdict: FSP Hydro Ti Pro 1000W ATX 3.1 is a high-efficiency choice for enthusiasts building next-gen systems with ATX 3.1 cases. It suits users who demand silent operation and maximum power density.

Specifications side by side

FSP Power Supply Models Compared

FSP offers distinct options based on form factor and efficiency. The FSP 400W Gold Flex ATX Mini ITX Power Supply delivers 80 Plus Gold efficiency in a compact 1.6-inch width, ideal for modest Mini ITX builds. For tighter spaces, the FSP FlexGURU 500W Flex ATX PSU provides similar Gold efficiency in a 1.59-inch width, suited for 1U systems. These units prioritize high performance in small footprints.

Other models focus on standard compatibility or next-gen standards. The FSP SFX Pro 450W Bronze Power Supply offers 80 Plus Bronze efficiency in a slightly larger 4-inch width, fitting small office PCs. The FSP Hydro Ti Pro 1000W Titanium ATX 3.1 PSU targets high-end enthusiasts with ATX 3.1 compliance and maximum power density. Each unit serves specific build requirements.

Where FSP Fits Your Build

FSP’s current lineup targets small form factor and high-density builds. You have options ranging from the ultra-compact 400W Mini ITX unit to the standard 450W SFX model. The range extends to specialized Flex ATX and full-size ATX 3.1 units. Efficiency ratings span Bronze to Titanium. However, this list lacks high-wattage standard ATX options for large cases. It also does not include non-modular or fully modular units outside the specific Flex and Mini ITX niches. You should verify your case dimensions before choosing.

How to choose the right FSP power supply

1. Match form factor to case

   Start by checking your case dimensions. The FSP 400W Gold Flex ATX Mini ITX Power Supply measures just 1.6 inches wide. This tiny footprint fits tight Mini ITX builds. If you need more space, the FSP SFX Pro 450W Bronze Power Supply is wider at 4 inches. Choose the size that physically fits your chassis. Incorrect dimensions mean the unit will not install. Measure your available space before selecting a model. Width and height are critical for small cases. Length also matters for cable routing. Ensure the selected unit fits without forcing components.

2. Select efficiency rating wisely

   Efficiency ratings indicate power conversion quality. The FSP 400W Gold Flex ATX Mini ITX Power Supply offers 80 Plus Gold certification. This means less wasted energy and lower heat output. The FSP SFX Pro 450W Bronze Power Supply provides 80 Plus Bronze efficiency. Bronze is sufficient for office PCs but generates more heat than Gold. Higher ratings cost more but save electricity over time. Choose Gold or Titanium for high-performance systems. Bronze works for basic tasks. Check the rating label on the spec sheet. This spec directly impacts your power bill and cooling needs.

3. Check ATX version compatibility

   Newer standards support modern hardware. The FSP Hydro Ti Pro 1000W Titanium ATX 3.1 PSU supports ATX 3.1. This version handles high-power GPUs and new connectors. Older units may lack these features. If you build with recent graphics cards, ensure your PSU matches the case and GPU requirements. ATX 3.1 offers better power delivery stability. It also includes necessary cables for next-gen components. Verify your motherboard and GPU support the version. Mismatched versions can cause compatibility issues. Always check the ATX version listed in the specs. This ensures your system runs reliably under load.

4. Consider Flex ATX for 1U systems

   Flex ATX units suit specific server or 1U builds. The FSP FlexGURU 500W Flex ATX PSU is designed for these tight spaces. It offers 80 Plus Gold efficiency in a small form. This model fits SFF cases or specialized enclosures. Standard ATX or SFX units may not fit. Check the width and height carefully. Flex ATX units often have different connector layouts. Ensure your case supports this specific form factor. The FSP FlexGURU provides reliable power for dense builds. It balances efficiency with compact dimensions. Verify compatibility before purchase to avoid installation failures.

5. Verify weight and mounting

   Weight affects mounting stability in small cases. The FSP 400W Gold Flex ATX Mini ITX Power Supply weighs 2 pounds. The FSP SFX Pro 450W Bronze Power Supply is heavier at 2.69 pounds. Heavier units may require additional support in lightweight cases. Check your case mounting points. Ensure screws align with the PSU holes. Lighter units might shift if not secured properly. Consider the total system weight. Heavy GPUs can strain small form factor cases. A stable PSU prevents vibration and noise. Verify the weight spec matches your case capabilities. This ensures long-term reliability and safety.

Frequently asked questions

See also

• fsp group mini itx solution flex vs sfx pro 450w power
• best FSP PC power supplies under 150
• best ARrase PC cases
• best gaming chairs for PC