Apevia TFX-AP300W 300W TFX Power Supply
4.4Editor score
Standard TFX form factor
80mm cooling fan included
Full protection suite
In this guide
Choosing the right power supply is critical for small form factor builds. A reliable 300W PSU ensures stable performance without overheating or electrical issues in tight spaces.
We evaluated ten top models based on efficiency ratings, build quality, fan noise, and compatibility. Each unit was analyzed for real-world use in HTPCs, mini PCs, and industrial setups.
Our picks showcase diverse options from budget-friendly to premium modular designs. Prices and availability fluctuate frequently, so verify current details before purchasing your next power unit.
Top 3 Picks for Best 300W PSU
FSP FlexGURU 300W Flex ATX Power Supply
4.6Editor score
80 PLUS GOLD certified efficiency
Fully modular cable design
Japanese electrolytic capacitors
Silverstone Technology TX300-VT
5.0Editor score
Ultra quiet 18 dBA fan
24/7 continuous operation
Single PCIe 6pin support
Top 10 Best 300W PSU in 2026 Compared
Below is a side-by-side comparison of all ten selected power supplies. This table highlights key specifications and unique attributes to help you decide quickly.
ProductsSpecificationsEditor scorePrice
Best Budget
Apevia TFX-AP300W
300W continuous output
80mm forced air fan
Input 115-230V AC
Standard TFX design
4.4Editor score
Editor's Choice
Thermaltake Smart 500W
500W continuous output
80 PLUS White certified
120mm ultra quiet fan
5 year warranty
4.6Editor score
Editor's Choice
FSP FlexGURU 300W
80 PLUS GOLD efficiency
Fully modular cables
Japanese capacitors
Industrial grade safety
4.6Editor score
Silverstone TX300-VT
300W at 40C
80 PLUS Bronze rated
18 dBA minimum noise
Fixed cable design
5.0Editor score
Apevia ITX-AP300W
SFF Mini-ITX compatible
40mm double bearing fan
Manual voltage switch
Separable connectors
3.9Editor score
FSP Group FSP300-60THA
ATX12V standard
300W desktop PSU
Standard connectors
Reliable brand
5.0Editor score
Seasonic SSP-300SFG
80 Plus Gold certified
SFX form factor
Active PFC
V2.31 standard
Supermicro PWS-305-PQ
High quality product
ATX power supply
300W output
Enterprise grade
HP Power Supply ATX 300W
Original HP unit
ATX standard
PFC active
Replacement PSU
ATX-300TA-300W
Check part number
ATX compatibility
300W total power
Functionality verified
1. FSP FlexGURU 300W Flex ATX Power Supply – Best Overall 300W PSU
FSP FlexGURU 300W Flex ATX Power Supply
90% typical efficiency
Fully modular design
Japanese capacitors
Industrial safety features
The FSP FlexGURU is a top tier power supply for compact industrial builds. It holds a strong 4.6 rating from users who value efficiency and reliability in tight spaces.
Pros
- High 80 PLUS GOLD efficiency
- Clean modular cable setup
- Durable Japanese components
- Excellent industrial safety
- Quiet operating levels
Cons
- Higher price point
- Specialized flex ATX size
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This unit shines with its 80 PLUS GOLD certification, delivering up to 90% efficiency at typical loads. The fully modular design with all black ribbon cables keeps your case tidy and airflow optimal. Japanese electrolytic capacitors ensure it can run 24/7 without failing even in hot environments.
While the price is higher than standard units, the durability justifies the cost. Some users note the specialized mounting requires specific brackets, but FlexGuru series brackets are often included or adaptable to most Flex-ATX chassis.
Buy this if you need a reliable workstation or NAS power source. It is ideal for edge computing where stability and low noise are critical for long term uptime.
Superior Energy Efficiency
High efficiency reduces heat and energy costs significantly over time compared to lower rated units.
Professional Cable Management
Modular cables eliminate clutter inside small cases improving airflow and cooling performance dramatically.
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2. Apevia TFX-AP300W 300W TFX Power Supply – Best Budget 300W PSU
Apevia TFX-AP300W 300W TFX Power Supply
300W flex ATX
80mm fan cooling
Input 115-230V
5% voltage tolerance
The Apevia TFX-AP300W is an excellent budget choice for entry level small form factor systems. Users appreciate its straightforward design and reliable 4.4 rating for general use cases.
Pros
- Affordable price point
- Standard TFX compatibility
- Includes 80mm cooling fan
- Full protection suite
- Simple installation
Cons
- Basic efficiency rating
- Fixed cables included
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This power supply delivers a solid 300W output suitable for basic office or home PC builds. It features standard 115-230V input for global compatibility and includes all necessary protection circuits like OVP and SCP. The 80mm fan ensures adequate forced air ventilation to keep components cool during operation.
The trade-off is that it lacks high efficiency certifications and uses fixed cables. However, for users prioritizing cost over modularity or premium efficiency, this unit offers exceptional value for its price bracket.
Recommend this for basic HTPC or POS terminals where budget is the main concern. It fits standard TFX chassis easily and provides the essential power needed for non-demanding systems.
Global Voltage Support
Automatic input adjustment allows use in different regions without requiring manual switch changes.
Essential Safety Features
Full protection suite guards against surges and shorts to protect your valuable system components.
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3. Silverstone Technology TX300-VT – Best Premium 300W PSU
Silverstone Technology TX300-VT
80 PLUS Bronze rated
18 dBA minimum noise
24/7 continuous operation
Fixed cable design
Silverstone TX300-VT stands out with a rare 5.0 rating reflecting exceptional user satisfaction. It is designed for environments where noise reduction and stability are absolutely paramount for daily operations.
Pros
- Perfect 5.0 user rating
- Extremely quiet 18 dBA
- Rated for continuous 24/7
- 80 PLUS Bronze efficiency
- Single PCIe connector
Cons
- Fixed cable layout
- Premium pricing
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This unit delivers 300W at 40C with Bronze efficiency while operating at only 18 dBA minimum noise levels. The design is rated for 24/7 continuous operation making it perfect for always-on systems. It supports a single PCI-E 6pin connector for light GPU add-ons if needed.
While it uses fixed cables which can limit flexibility, the quiet performance justifies the setup. Some users may find the price high compared to competitors but the engineering quality is evident in its longevity.
Ideal for silent home office or media center builds. If you need a power supply that simply works without making noise or heat, this model is the top choice for quiet reliability.
Ultra Quiet Operation
The 80mm fan is engineered to run as low as 18 dBA for near silent performance in shared spaces.
Reliable Continuous Duty
Engineered to handle non stop operation without throttling or thermal shutdown issues over time.
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4. Thermaltake Smart 500W – Best for 500W Output
Thermaltake Smart 500W
500W continuous output
80 PLUS White certified
120mm ultra quiet fan
Active PFC
The Thermaltake Smart 500W offers significantly higher power than standard 300W units. It is a great option if you need extra headroom for future upgrades or heavier system loads.
Pros
- Higher 500W power capacity
- Includes active PFC support
- 120mm cooling fan
- Five year warranty
- Supports 2 PCIe connectors
Cons
- Larger ATX size
- White efficiency tier
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This PSU delivers 500W continuous output at 40C with White certification ensuring 80% efficiency. It includes active PFC for better power factor correction and comes with a large 120mm fan for silent cooling. It also supports two PCI-E connectors which is rare for entry units.
The main drawback is its standard ATX size which may not fit very small cases. Users looking for compact SFF might need larger chassis than standard Flex-ATX designs to accommodate this larger form factor effectively.
Choose this if you plan to upgrade your GPU later. The extra wattage gives flexibility for future system expansion without needing a second power supply purchase or complex mods.
Power Headroom
500W capacity supports mid range graphics cards and allows room for future component upgrades easily.
Extended Warranty
Comes with a full five year warranty providing long term peace of mind for system reliability.
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5. Apevia ITX-AP300W – Best for Mini ITX
Apevia ITX-AP300W
Mini-ITX compatible
40mm double bearing fan
Separable connectors
Manual voltage switch
The Apevia ITX-AP300W is engineered specifically for Mini-ITX and 1U server cases. Its compact dimensions make it an ideal solution for tight builds where standard ATX units simply cannot fit.
Pros
- Perfect for SFF chassis
- Separable main connectors
- Double bearing fan
- Compact dimensions
- Includes safety suite
Cons
- Lower rating than others
- Requires manual voltage setup
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It features a manual voltage switch preset to 115V and includes separable 20+4 and 4+4 connectors for flexibility. The 40mm fan has double ball bearings for longer life and better airflow in confined spaces. It provides essential SATA and Molex ports for storage drives.
Users note the rating is lower at 3.9 likely due to the manual switch complexity. International users must toggle to 230V manually or risk damage. Also the fan is small and may be louder under high load than larger fans.
Buy this for small media boxes or compact desktops. It fits standard ITX chassis and offers necessary features for basic builds without breaking the bank on custom solutions.
Compact Dimensions
Measures only 5.9 by 3.21 by 1.59 inches fitting most Mini ITX cases perfectly.
Flexible Connectors
Separable main and CPU cables allow usage with both modern and legacy motherboards easily.
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6. FSP Group FSP300-60THA – Standard ATX Choice
FSP Group FSP300-60THA
ATX12V standard
300W desktop PSU
FSP brand reliability
9PA3007712 model
The FSP FSP300-60THA is a straightforward desktop power supply for standard ATX systems. It earns a perfect 5.0 rating from users who value reliability and brand reputation over fancy features.
Pros
- Perfect 5.0 rating
- Standard ATX compatibility
- FSP proven reliability
- Simple desktop unit
- Wide availability
Cons
- Basic specifications
- No efficiency label
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This unit delivers 300W in a standard ATX form factor for easy installation in most PC cases. FSP is a well known manufacturer of power units ensuring build quality and safety standards are met consistently. The model 9PA3007712 is widely used in commercial desktops.
It lacks explicit efficiency ratings or modular cables but works reliably for general office tasks. Users appreciate the simple plug and play nature without complex cable management requirements or extra mounting brackets needed.
Select this for standard office PCs or replacements for old desktop towers. It offers solid performance at a fair price point for those who prioritize stability and ease of use.
Proven Brand
FSP is a trusted global supplier ensuring consistent quality and reliable components in every unit.
Universal Fit
Standard ATX dimensions allow fitting into almost any desktop PC chassis without modification.
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7. Seasonic SSP-300SFG – Best SFX Gold
Seasonic SSP-300SFG
SFX form factor
80 Plus Gold rated
Active PFC
ATX 12V V2.31
The Seasonic SSP-300SFG is a premium compact unit for SFX cases. It carries Gold efficiency and Active PFC for high performance in tight spaces where size matters most.
Pros
- SFX compact size
- 80 Plus Gold efficiency
- Seasonic quality
- Active PFC support
- V2.31 standard
Cons
- N/A rating
- Premium price
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This supply delivers 300W in a small SFX size perfect for mini gaming builds. It meets ATX 12V V2.31 standards and includes Active PFC for improved efficiency. Seasonic is renowned for exceptional build quality and silence in their PSU designs.
The rating is marked N/A due to limited current data but Seasonic units typically perform well. Users may find it expensive compared to non modular units. However Gold efficiency means lower power bills and heat generation over time.
Buy this for mini ITX gaming rigs needing high efficiency. It fits SFX cases easily and offers the reliability of a top tier brand in a compact package.
Gold Efficiency
80 Plus Gold certification ensures less wasted energy and lower electricity costs over the lifespan.
SFX Form Factor
Small SFX size allows installation in mini ITX chassis with more room for cooling and GPUs.
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8. Supermicro PWS-305-PQ – Best for Server Use
Supermicro PWS-305-PQ
High quality product
ATX power supply
300W output
Enterprise grade
The Supermicro PWS-305-PQ is a high quality power supply tailored for server environments. Users note its outstanding quality and value compared to generic alternatives in the market.
Pros
- Enterprise grade quality
- High quality components
- Excellent reliability
- Brand trusted
- Good value
Cons
- N/A rating
- Limited details
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This unit offers premium build quality suitable for professional use. It delivers 300W with standard ATX connectors fitting many workstation servers. Supermicro is a trusted brand in data centers ensuring consistent safety and performance standards.
Data is limited but users report excellent satisfaction and reliability. It may lack consumer features but the focus is on stability and longevity for 24/7 server operations and office workstations.
Recommend for server replacements or professional workstations. If you need a power supply that runs reliably 24/7 without failure this is a smart professional choice.
Enterprise Reliability
Built to enterprise standards ensuring long service life and minimal downtime in server racks.
Professional Quality
High quality components ensure better performance under load than standard consumer grade units.
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9. HP Power Supply ATX 300W – Best for HP PCs
HP Power Supply ATX 300W
Original HP unit
ATX standard
PFC active
300W total
The HP Power Supply ATX 300W is an original OEM unit for HP desktops. It is designed specifically to fit and function with HP systems without modification or adapters.
Pros
- Original equipment unit
- Perfect OEM fit
- Active PFC
- Reliable brand
- Simple replacement
Cons
- N/A rating
- OEM specific
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This unit is 300W with Active PFC ensuring stable performance for HP business machines. It matches the original specifications so it fits exactly without clearance issues. Users looking to restore HP PCs to original specs appreciate this direct fit.
Ratings are N/A but OEM units generally work flawlessly in their native environment. It may not have the features of a retail unit but guarantees compatibility with your specific chassis and connectors.
Choose this if restoring an HP machine to original specs. It avoids compatibility issues and ensures your system runs as intended by the manufacturer.
OEM Fit
Designed specifically for HP chassis ensuring perfect mounting and connector alignment without mods.
Active PFC
Includes Active Power Factor Correction for efficient power draw and system stability.
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10. ATX-300TA-300W – Verify Before Use
ATX-300TA-300W
Check part ATX-300TA
ATX compatible
300W power
Verify functionality
The ATX-300TA-300W is a generic model number requiring verification. Buyers must check functionality and compatibility with their equipment before installing it in a system.
Pros
- ATX compatible
- 300W output
- Functional verification
- Standard design
- Potential OEM match
Cons
- Verify compatibility
- Limited details
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This unit delivers 300W in a standard ATX format. The description emphasizes checking part numbers to ensure fit and function. It may match older OEM units but requires careful confirmation of connector types and mounting points.
Users should inspect all connectors match their motherboard and case. While the rating is not available verified units generally work if they match original specs. Always test before permanent installation.
Use this if you need a generic replacement and verify specs first. Confirm part ATX-300TA matches your needs to avoid returns or fit issues during installation.
Verify Compatibility
Always check part number and connectors before buying to ensure they match your existing equipment.
Standard Fit
ATX form factor allows installation in most standard desktop chassis with minimal adjustments needed.
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Buying Guide – How to Choose the Best 300W PSU
Selecting the right power supply involves more than wattage. Consider form factor, efficiency, cables, and safety features to ensure compatibility and longevity.
Form Factor Compatibility
Small form factor cases require specific PSU types like TFX, ITX, or SFX. Standard ATX units may not fit compact enclosures and need adapters or custom brackets.
Always check your case specifications before buying to ensure the power supply dimensions and mounting points match your chassis requirements.
Efficiency Ratings
80 PLUS Bronze, Gold, or higher certifications indicate how efficiently the unit converts AC power to DC. Higher efficiency means less waste heat and lower electricity costs.
For always-on systems like NAS or servers, invest in 80 PLUS GOLD to reduce long-term operating costs and thermal load.
Cable Type
Modular cables allow you to use only what you need reducing clutter inside small cases. Fixed cables are cheaper but can hinder airflow in tight spaces.
Choose fully modular if you prioritize aesthetics and airflow or standard non-modular if budget is the primary concern for your build.
Fan and Noise
Smaller fans on TFX or SFX units tend to spin faster and can be no louder under load. Look for low decibel ratings if the unit will be in a quiet office.
Prioritize models with larger fans or optimized airflow design if you need the lowest possible noise levels during operation.
Connector Availability
Ensure the PSU has enough SATA, Molex, and PCIe connectors for your devices. Some compact units have fewer ports which can limit storage or expansion options.
Count your current components and future plans to confirm the power supply provides enough ports without needing expensive adapters or splitters.
Protection Features
Look for OVP, OCP, SCP, and OTP protections to safeguard your hardware from electrical issues. Industrial grade safety is crucial for 24/7 continuous operation setups.
Do not skip safety protections. A good PSU protects your motherboard and drives from power surges and shorts that could otherwise destroy your system.
Warranty Support
Warranty lengths vary from one to five years. Longer warranties indicate manufacturer confidence in the product and provide better long-term security for your investment.
Check warranty terms before purchasing to ensure you have coverage for replacement or repair if the unit fails prematurely.
Voltage Switching
Some units require manual voltage switching between 115V and 230V. Others auto switch. Ensure the model you choose matches your local power grid to avoid damage.
If traveling internationally verify the voltage switch setting. Using 115V in 230V regions can destroy the power supply and connected hardware instantly.
How to Use and Care for Your 300W PSU
Install the power supply securely using all mounting points to prevent vibration damage. Ensure the unit is oriented so the fan blows air into or out of the case as designed.
Connect cables firmly to both the PSU and components to avoid loose contacts that can cause short circuits. Check that connectors are fully seated before powering on the system.
Dust the unit regularly to prevent overheating. Use compressed air to clear dust from the fan and vents keeping it clean for optimal airflow and cooling performance.
Frequently Asked Questions
Is 300W enough for a gaming PC?
A 300W PSU is typically sufficient only for low-power integrated graphics or very old dedicated cards. Modern gaming GPUs usually require at least 450W to 650W for stable performance and safety.
What is the difference between TFX and ATX?
TFX is a smaller form factor designed for compact cases while ATX is standard size. TFX units have different mounting holes and cable lengths to fit tight spaces like home theater PCs.
Do I need a modular PSU for a small build?
Not strictly but modular helps cable management. Fixed cables can still work but may clutter your case. Modularity is a premium feature for those who value clean airflow and looks.
Why do industrial PSUs cost more?
Industrial units use higher quality capacitors and safety protections for 24/7 operation. They often offer better efficiency and reliability justifying the higher price compared to consumer grade models.
Can I use a 500W PSU in a small case?
If the dimensions match. Size matters more than wattage. Ensure your case supports ATX or TFX size regardless of wattage. 500W units are usually larger than compact 300W options.
What does 80 PLUS mean?
80 PLUS certifies efficiency levels. Higher tiers like Gold mean the PSU wastes less energy as heat. This reduces power costs and improves stability for sensitive computer systems.
How long should a power supply last?
Quality units can last five to ten years. Look for brands with good warranties. Proper airflow and dust cleaning extend lifespan significantly. Replace if you notice strange noises or power issues.
Do I need active PFC?
Active PFC improves power efficiency and ensures better compatibility with voltage variations. It is standard in most modern units and helps reduce the load on your electrical system.
Final Thoughts on Choosing the Best 300W PSU
We highlighted the FSP FlexGURU for overall performance, Apevia TFX for budget needs, and Silverstone for silent operation. Each offers unique strengths for different compact PC applications.
Prioritize form factor and safety features when selecting. Efficiency and noise levels also matter for long term comfort and reliability in daily usage scenarios.
Remember prices and stock fluctuate often. Verify current availability and specifications before finalizing your purchase to ensure you get the best value available today.