FSP 400W Gold Flex ATX or FSP SFX Pro 450W Bronze? Which FSP Model to Buy
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This comparison of the fsp group mini itx solution flex vs sfx pro 450w power units helps you pick the right small form factor supply. Both options deliver stable power for compact builds, but they target different case standards. The FSP 400W Gold Flex uses a proprietary Mini ITX shape for extreme thinness. The FSP SFX Pro 450W follows standard SFX dimensions. You need to check your case compatibility first. Efficiency ratings also differ between these two models. This guide breaks down the key specs to help you decide.
Key differences
| Aspect | FSP 400W Gold Flex ATX Mini ITX Power Supply | FSP SFX Pro 450W Bronze Power Supply |
|---|---|---|
| Efficiency Rating | 80 Plus Gold | 80 Plus Bronze |
| Form Factor | Mini ITX | SFX |
| Wattage | 400W | 450W |
| Dimensions | 1.6 x 3.25 x 5.9 inches | 4 x 2.5 x 5 inches |
| Modularity | Not listed | Not listed |
Which one should you choose?
Choose FSP 400W Gold Flex ATX Mini ITX Power Supply if
- You need a power supply that fits in ultra-thin Mini ITX cases.
- You prioritize higher efficiency ratings for better energy savings.
- You require a 4 cm fan for specific airflow constraints.
Choose FSP SFX Pro 450W Bronze Power Supply if
- You want a standard SFX form factor for wider case compatibility.
- You need higher wattage output for slightly more demanding components.
- You prefer an included adapter bracket for ATX case installation.
Verdict: Choose the FSP 400W Gold Flex if your case strictly requires the Mini ITX form factor or you want higher efficiency. Pick the FSP SFX Pro 450W if you need standard SFX dimensions and extra wattage. Both units provide reliable power for small builds.
FSP Flex Gold vs SFX Pro Bronze
efficiency rating
The FSP 400W Gold Flex ATX Mini ITX Power Supply earns 80 Plus Gold certification, meaning it converts more than 90% of input power into usable energy at typical loads. This high efficiency reduces heat and wasted electricity. The FSP SFX Pro 450W Bronze Power Supply holds 80 Plus Bronze certification. While still efficient, Bronze standards require less energy conversion than Gold. For users prioritizing lower power draw and reduced heat output in a sealed chassis, the Gold unit offers a clear technical advantage. The Bronze unit remains reliable but falls short on maximum efficiency metrics.
form factor
Form factor dictates physical compatibility with your case. The FSP 400W Gold Flex uses the Mini ITX standard, measuring 1.6 inches in height. This ultra-slim profile fits tightest into small builds but may limit airflow. The FSP SFX Pro 450W Bronze follows the SFX standard, measuring 2.5 inches in height and 4 inches in width. SFX units are slightly larger but often easier to cool. Crucially, the SFX Pro includes a free adapter bracket to fit standard ATX cases. If you need maximum flexibility for different case sizes, the SFX unit wins. If you need the smallest possible footprint, the Flex unit wins.
wattage output
Total power delivery matters for component selection. The FSP SFX Pro 450W Bronze Power Supply provides 450 watts of continuous power. The FSP 400W Gold Flex ATX Mini ITX Power Supply provides 400 watts. The SFX unit offers 50 watts more headroom. This extra power can support slightly more demanding components or future upgrades without straining the supply. For builds requiring maximum power in a small package, the SFX Pro has the advantage. The Flex unit is sufficient for lighter systems but offers less total energy capacity.
fan size
Cooling mechanics differ significantly between these units. The FSP 400W Gold Flex ATX Mini ITX Power Supply uses a 4 cm fan. Small fans often spin faster to move air, which can increase noise levels under load. The FSP SFX Pro 450W Bronze Power Supply uses a larger sleeve fan with intelligent speed control. Larger fans generally move more air at lower speeds, potentially offering quieter operation. The SFX unit also adjusts speed based on temperature for better thermal management. For users sensitive to noise or seeking smoother airflow, the SFX Pro is the better choice.
cable design
Cable management impacts build aesthetics and airflow in small cases. The FSP SFX Pro 450W Bronze Power Supply features all-black ribbon cables. These flat cables are easier to route through tight spaces and look cleaner inside compact chassis. The FSP 400W Gold Flex ATX Mini ITX Power Supply does not specify cable type in the provided data. If cable routing is a priority for your build, the SFX unit offers a clear advantage with its tailored ribbon design. For users who replace cables entirely, this difference may be less relevant.
Which FSP Power Supply Fits Your Build
Strict Mini ITX builders needing high efficiency
Choose the FSP 400W Gold Flex if your case strictly requires a Flex ATX form factor. Its 400W output and 80 Plus Gold rating ensure over 90% efficiency. The compact 1.6-inch height fits tight Mini ITX chassis where standard SFX units will not fit. You get reliable power in a size that matches your specific case constraints.
SFX case users wanting more wattage
Pick the FSP SFX Pro 450W if your case supports the SFX form factor. You gain 50W of extra power compared to the Flex model. The DC-to-DC design provides stable voltage regulation. It includes an adapter bracket to fit standard ATX cases, offering flexibility. The intelligent fan keeps noise low while delivering consistent performance for your system.
Users prioritizing efficiency and low heat
Select the FSP 400W Gold Flex for superior energy conversion. The 80 Plus Gold certification means less wasted energy and lower heat output. This efficiency is critical for small builds that trap heat. The 4 cm fan operates quietly while maintaining airflow. You benefit from reduced power consumption and a cooler operating environment for your components.
Budget builders seeking reliable daily performance
The FSP SFX Pro 450W offers solid Bronze efficiency for daily office use. Its 450W capacity handles standard components reliably. The all-black ribbon cables simplify cable management in compact cases. You get a robust DC-to-DC structure for consistent power delivery. This unit balances cost and performance for users who need dependable power without premium efficiency ratings.
The products compared
FSP 400W Gold Flex ATX Mini ITX Power Supply
Best for: Compact high-efficiency builds
- 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 unit delivers 400W of power with 80 Plus Gold efficiency. It uses a 4 cm fan for quiet cooling in small cases. The 6+2 pin PCIe connector supports modern graphics cards. Its compact Mini ITX form factor fits tight builds. You get reliable performance for standard or advanced systems. It suits users who need high efficiency in a small space.
Pros
- 80 Plus Gold certification for efficiency over 90%
- 400W output capacity
- Includes 1x PCIe 6+2 pin connector
- Compact Mini ITX dimensions
Cons
- Smaller 400W output compared to 450W alternatives
- Tiny 4 cm fan size
- Heavier at 2 pounds
Good fit if
- You need high efficiency in a Mini ITX case
- You require a 6+2 pin PCIe connector
- You prioritize quiet operation in a small form factor
Skip if
- You need more than 400W of power
- You prefer standard ATX form factors
- You want a larger fan for easier maintenance
Verdict: FSP 400W Gold Mini ITX PSU is a solid choice for Mini ITX builds needing high efficiency. It fits users who value compact size and quiet cooling over raw wattage.
FSP SFX Pro 450W Bronze Power Supply
Best for: Small form factor systems and budget ATX builds
- 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 built for small form factor builds. It delivers 450W of power with 80 PLUS Bronze efficiency. The unit uses a DC-to-DC design for stable voltage regulation. It includes an intelligent sleeve fan that adjusts speed based on temperature. Flat black ribbon cables help with cable management in tight spaces. An included adapter bracket allows installation in standard ATX cases.
Pros
- 450W output capacity
- 80 PLUS Bronze efficiency rating
- DC-to-DC module design for reliable voltage regulation
- Intelligent sleeve fan adjusts speed to temperature
- Includes SFX-to-ATX adapter bracket for versatile case compatibility
Cons
- 80 PLUS Bronze efficiency is lower than Gold-rated competitors
- 450W wattage is lower than the 400W Gold Flex alternative's relative efficiency tier
- No mention of modular cable management
Good fit if
- You need a reliable PSU for budget small form factor builds
- You plan to install the unit in a standard ATX case using the included adapter
- You prioritize stable voltage regulation for essential PC components
Skip if
- You require 80 PLUS Gold efficiency for maximum power savings
- You need more than 450W of continuous power output
- You prefer fully modular cables for cleaner builds
Verdict: FSP SFX Pro 450W Bronze is a solid choice for users who need a compact, reliable power source for small cases or standard ATX enclosures with the adapter. It suits budget builds where Bronze efficiency and DC-to-DC stability are sufficient.
Specifications side by side
| Spec | FSP 400W Gold Flex ATX Mini ITX Power Supply | FSP SFX Pro 450W Bronze Power Supply |
|---|---|---|
| Wattage | 400W | 450W |
| Efficiency Rating | 80 Plus Gold | 80 Plus Bronze |
| Modularity | not stated | Non-Modular |
| PCIe Connector Type | 6+2 pin | not stated |
| Fan Size | 4 cm | not stated |
| Form Factor | Mini ITX | Mini ITX |
| Device Compatibility | not stated | PCs |
| Dimensions | 5.9 × 1.6 × 3.25 inches | 5 × 4 × 2.5 inches |
| Weight | 2 pounds | 2.69 pounds |
| Size | 400W_Gold | 450W |
| Model | FSP400-60FGGBA | PPA450AA01 |
| Color | not stated | 80 Plus Bronze |
Frequently asked questions
Can the FSP SFX Pro fit in a Mini ITX case?
Yes, the FSP SFX Pro 450W Bronze is designed for small form factor systems. It features an SFX form factor measuring 4 inches wide by 2.5 inches high. This size allows it to fit in many Mini ITX cases that accept SFX units, offering a reliable power source for compact builds.
Which PSU is better for high efficiency?
The FSP 400W Gold Flex ATX is the better choice for efficiency. It holds an 80 Plus Gold rating, which typically ensures over 90% efficiency at typical loads. This reduces heat output and energy waste compared to the Bronze-rated SFX Pro, making it ideal for users prioritizing power savings in a compact build.
What are the physical dimensions of the FSP Flex Gold?
The FSP 400W Gold Flex ATX measures 5.9 inches in length, 1.6 inches in width, and 3.25 inches in height. It weighs 2 pounds. These compact dimensions allow it to fit into Mini ITX cases that strictly require the Flex ATX form factor, providing a space-saving solution for tight builds.
Does the SFX Pro have DC-to-DC stability?
Yes, the FSP SFX Pro 450W Bronze utilizes DC-to-DC technology for stability. This design choice ensures reliable power delivery for budget builds. It is suitable for users who need a compact, dependable power source for small cases or standard ATX enclosures when used with an adapter, balancing cost and performance.
Which unit weighs more?
The FSP SFX Pro 450W Bronze weighs 2.69 pounds, while the Flex Gold weighs 2 pounds. The SFX Pro is slightly heavier due to its different internal construction and form factor. This weight difference is minor but may matter if you are building a very lightweight portable PC.
Is the FSP Flex Gold suitable for budget builds?
The FSP Flex Gold is best for users who value compact size and quiet cooling over raw wattage. While it offers high efficiency, it is positioned for compact high-efficiency builds rather than pure budget constraints. If you need higher wattage on a budget, the SFX Pro might be more suitable.
Can I use the SFX Pro in a standard ATX case?
Yes, the FSP SFX Pro can be used in standard ATX enclosures with an adapter. It is designed for small form factor systems but offers versatility. This makes it a solid choice for users who need a compact power source that can adapt to different case types, including standard ATX setups.