Choosing a compact SFX power supply for small form factor PC builds
The FSP450-50SAC is a specialized SFX power supply designed specifically for Mini-ITX and Micro-ATX cases where space is at a premium. Unlike standard ATX units, this 450W Bronze-rated PSU sacrifices modular cabling to maintain reliability in constrained builds where every cubic inch matters.
Key Considerations Before Buying
- SFX form factor compatibility is non-negotiable for Mini-ITX cases; this FSP unit measures 100mm x 125mm x 63.5mm, fitting cases that reject standard ATX power supplies.
- The 80 Plus Bronze certification indicates 82-85% efficiency at typical loads, balancing energy savings against the premium cost of higher efficiency ratings in this compact category.
- Non-modular design means all cables are permanently attached, which can complicate cable management in extremely tight cases but eliminates potential connection issues from modular interfaces.
What Our Analysts Recommend
For SFX power supplies, examine the fan size and bearing type—this FSP uses a 80mm fan with sleeve bearing, adequate for its thermal envelope. Check the +12V rail amperage (37A here) to ensure it can handle your CPU and GPU combination, as this single rail design simplifies power distribution in compact builds.
Internal Power Supplies Market Context
Market Overview
The SFX power supply market has expanded beyond niche applications as Mini-ITX gaming and HTPC builds gain popularity, creating demand for reliable compact units under 500W. FSP competes against Corsair's SF series and SilverStone's SFX-L offerings in this specialized segment where physical dimensions trump raw wattage.
Common Issues
Compact power supplies often struggle with thermal management due to smaller fans and tighter component spacing, potentially leading to louder operation under load. Non-modular SFX units like this FSP model present cable routing challenges in cases with minimal clearance behind motherboard trays.
Quality Indicators
Look for Japanese capacitors (this FSP uses Teapo and CapXon), adequate warranty length (3 years here), and proper OCP/OVP/SCP protections. The 4.44 Amazon rating with 235 reviews suggests reasonable field reliability, though the adjusted 4.20 accounting for suspicious reviews provides a more conservative estimate.
Review Authenticity Insights
Grade B Interpretation
A Grade B authenticity rating with 10% estimated fake reviews indicates generally trustworthy feedback with minor manipulation concerns. For this FSP unit, this means approximately 24 of the 235 reviews may be inauthentic, but the overwhelming majority reflect genuine user experiences.
Trust Recommendation
Focus on verified purchase reviews that mention specific Mini-ITX case compatibility (like the Node 202 or SG13) or discuss thermal performance during gaming sessions. The high percentage of authentic reviews suggests the reported reliability and noise levels are likely accurate representations.
Tips for Reading Reviews
Prioritize reviews that detail installation in specific small form factor cases and mention long-term performance over 6+ months. Look for mentions of coil whine under low load or fan ramp-up behavior, as these are specific pain points for compact power supplies.
Expert Perspective
The FSP450-50SAC represents a competent entry in the value segment of SFX power supplies, offering essential 80 Plus Bronze efficiency without premium features like modular cables or semi-passive operation. Its 4.20 adjusted rating from authentic reviews suggests it delivers reliable power for modest Mini-ITX builds using processors like the Ryzen 5 5600G or Intel Core i5-12400 with integrated graphics. The three-year warranty provides reasonable protection given its price positioning below Corsair's SF450.
Purchase Considerations
This unit makes most sense for builders prioritizing case compatibility over cable management, particularly in budget-conscious Mini-ITX projects where the $20-30 savings versus modular alternatives matters. Consider your case's cable routing options carefully, as the fixed cables may create clutter in cases with under 15mm of clearance behind the motherboard tray.
Comparing Alternatives
Shoppers should compare this against the EVGA 450 GM and SilverStone SST-SX450-B, which offer similar wattage in SFX form factor with different fan configurations and warranty terms.
