Seasonic 300W Flex ATX Gold vs Seasonic Focus V4 GX-1000 1000W: Spec Comparison
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
When you compare the seasonic ssp 300sug 300w 80 plus vs focus v4 gx 1000 1000w, you see two distinct goals. Both units carry the 80 PLUS Gold efficiency rating, ensuring reliable power conversion for your system. The main difference lies in their form factor and power output. One is a compact Flex ATX unit designed for small enclosures, while the other is a full-size ATX power supply built for high-end desktops. You must choose the size that fits your case and the wattage your components require.
Key differences
| Aspect | Seasonic 300W Flex ATX Gold Power Supply | Seasonic Focus V4 GX-1000 1000W PSU |
|---|---|---|
| Wattage | 300W | 1000W |
| Form Factor | Flex ATX | ATX |
| ATX Version | ATX 12 V v 2.31 | ATX 3 |
| Modularity | not listed | Full-Modular |
| PCIe Connector | not listed | 12V-2x6 |
Which one should you choose?
Choose Seasonic 300W Flex ATX Gold Power Supply if
- You need a low-power supply for a compact industrial or small form factor build.
- Your case only supports the smaller Flex ATX dimensions.
- You require active PFC for efficient power factor correction in a budget build.
Choose Seasonic Focus V4 GX-1000 1000W PSU if
- You are building a high-end desktop that requires up to 1000W of power.
- You want full modularity for cleaner cable management in a standard ATX case.
- You need native support for the latest ATX 3.0 standard and PCIe Gen 5 connectors.
Verdict: Choose the Seasonic 300W Flex ATX Gold if your project demands a small footprint and modest power needs. Pick the Focus V4 GX-1000 if you are building a powerful gaming or workstation PC that requires high wattage and modern connectivity. Both offer solid efficiency, but their physical sizes and power capabilities serve completely different use cases.
Seasonic Flex vs Focus Specs
Wattage Output
The Seasonic 300W Flex ATX Gold Power Supply delivers 300 watts of power. This low output suits small, low-power builds or industrial applications. The Seasonic Focus V4 GX-1000 1000W PSU provides 1000 watts. This high capacity supports demanding gaming rigs and workstations. You must match the wattage to your system's total power draw. The Flex unit is limited to light loads. The Focus unit handles heavy loads with ease. Your choice depends entirely on your component power requirements.
Form Factor
The Seasonic 300W Flex ATX Gold Power Supply uses a Flex ATX form factor. This compact design fits into smaller cases or specialized enclosures. The Seasonic Focus V4 GX-1000 1000W PSU uses a standard ATX form factor. It measures 5.9 inches wide, 3.4 inches high, and 5.5 inches long. Standard ATX cases are widely available. Flex ATX cases are more niche. You need a case that supports your chosen form factor. The Flex unit offers size advantages for tight spaces.
ATX Version
The Seasonic 300W Flex ATX Gold Power Supply complies with ATX 12 V v2.31. This version supports standard desktop power requirements. The Seasonic Focus V4 GX-1000 1000W PSU complies with ATX 3. This newer standard includes support for modern graphics cards. It features a native 12V-2x6 PCIe connector. This cable handles high-power GPU transients better. You benefit from the newer standard if you have a modern GPU. The older version is sufficient for legacy or low-power systems.
Modularity
The Seasonic 300W Flex ATX Gold Power Supply does not list modularity in its specifications. It likely uses a fixed cable design. The Seasonic Focus V4 GX-1000 1000W PSU is fully modular. You can connect only the cables you need. This reduces clutter inside your case. It improves airflow and simplifies installation. Fixed cables can obstruct components in small builds. Full modularity offers better cable management. You will appreciate the flexibility of the Focus unit.
Efficiency Rating
Both units carry the 80 PLUS Gold efficiency rating. The Seasonic 300W Flex ATX Gold Power Supply achieves up to 90% efficiency at 50% load on 115 V AC input. The Seasonic Focus V4 GX-1000 1000W PSU also holds the Gold certification. This means both units convert electricity with high effectiveness. You will see similar energy savings from both. Neither unit holds an advantage here. Both are excellent choices for efficiency. You can trust the Gold rating on either model.
Which Seasonic PSU fits your build
Small form factor builder
You need a compact 300W unit for tight spaces. This Flex ATX model meets industrial safety standards and supports ATX 12V v2.31. Its small footprint fits mini-ITX cases where standard ATX power supplies cannot go. It is the right choice for low-power, space-constrained systems.
High-performance desktop user
You require 1000W for a powerful GPU and CPU. This unit features ATX 3 compliance and a 12V-2x6 PCIe connector for modern graphics cards. Full modularity keeps cables tidy, while the 135mm fan and Japanese capacitors ensure stable, quiet operation under heavy loads for years to come.
Industrial or embedded system integrator
You are building a system that prioritizes reliability and specific compliance. This power supply meets EMI and EMC safety standards. It uses an active PFC circuit and DC-to-DC converter design. These features provide consistent power delivery in environments where standard consumer power supplies might not suffice or fit.
The products compared
Seasonic 300W Flex ATX Gold Power Supply
Best for: Compact low-power industrial systems
- Wattage
- 300W
- Efficiency Rating
- 80 PLUS Gold
- ATX Version
- ATX 12 V v 2 31
- Power Factor Correction
- Active PFC
View on Amazon: Seasonic 300W Flex ATX Gold Power Supply Affiliate link
This Seasonic 300W Flex ATX power supply delivers 80 PLUS Gold efficiency with active PFC. It meets ATX 12 V v2.31 and EPS 12 V standards. The DC to DC converter design ensures stable power delivery. You should choose this unit for compact builds that require high efficiency and industrial-grade safety standards in a small form factor.
Pros
- 80 PLUS Gold efficiency rating
- Active PFC circuit design
- ATX 12 V v2.31 compliant
- EPS 12 V compliant
Cons
- Low 300W wattage limit
- Flex ATX form factor restricts case compatibility
- No mention of modular cabling
Good fit if
- You need a compact power supply for small form factor cases
- You require high efficiency for low power systems
- You want industrial-grade safety and EMI standards
Skip if
- You need more than 300W of power
- You require a standard ATX form factor
- You are building a high-performance gaming PC
Verdict: Seasonic 300W Flex ATX Gold PSU is a specialized unit for compact builds. It fits users who need high efficiency in a small space, not those requiring high power output.
Seasonic Focus V4 GX-1000 1000W PSU
Best for: High-end gaming and workstation builds
- Wattage
- 1000W
- Efficiency Rating
- 80 PLUS Gold
- Modularity
- Full-Modular
- ATX Version
- ATX 3
- PCIe Connector Type
- 12V-2x6
- Fan Size
- 135 mm
View on Amazon: Seasonic Focus V4 GX-1000 1000W PSU Affiliate link
This is a 1000W Seasonic power supply with 80 PLUS Gold efficiency. It uses a 135 mm fan and full-modular cabling. The unit supports ATX 3 and includes the 12V-2x6 PCIe connector for modern GPUs. Japanese capacitors ensure reliability. You need this for high-end builds requiring stable power delivery and efficient operation under heavy loads.
Pros
- 1000W output capacity
- 80 PLUS Gold efficiency rating
- 135 mm Fluid Dynamic Bearing fan
- Full-modular cabling design
- Includes 12V-2x6 PCIe Gen 5 cable
Cons
- 10-year warranty is shorter than some premium competitors
- Weighs 6.6 pounds, adding to system weight
- Lacks a built-in digital display for real-time monitoring
Good fit if
- You are building a high-end PC with a powerful GPU
- You want full-modular cabling for clean cable management
- You prioritize high efficiency for lower heat and noise
Skip if
- You need a power supply for a low-power office PC
- You require a 1600W or higher wattage unit
- You prefer a non-modular design for simplicity
Verdict: Seasonic Focus V4 GX-1000 1000W fits builders who need reliable, high-efficiency power for demanding graphics cards. It delivers the necessary connectors and capacity for top-tier systems without unnecessary bulk.
Specifications side by side
| Spec | Seasonic 300W Flex ATX Gold Power Supply | Seasonic Focus V4 GX-1000 1000W PSU |
|---|---|---|
| Wattage | 300W | 1000W |
| Efficiency Rating | 80 PLUS Gold | 80 PLUS Gold |
| Modularity | not stated | Full-Modular |
| ATX Version | ATX 12 V v 2 31 | ATX 3 |
| PCIe Connector Type | not stated | 12V-2x6 |
| Fan Size | not stated | 135 mm |
| Warranty | not stated | 10 Year |
| Form Factor | not stated | ATX |
| Power Factor Correction | Active PFC | not stated |
| Dimensions | not stated | 5.5 × 5.9 × 3.4 inches |
| Weight | not stated | 6.6 pounds |
| Color | Multicolor | not stated |
| Model | SSP-300SUG | PSUSEAFOCUSGX750V4 |
Frequently asked questions
Is the Seasonic 300W Flex ATX Gold compatible with standard ATX cases?
No, it is designed for Flex ATX form factor, which differs from standard ATX dimensions. You must verify your case supports the smaller Flex ATX standard before purchasing. This unit is intended for compact builds where space is limited, rather than full-sized towers. Using it in a standard case may require specific mounting adapters or result in fitment issues.
Does the Focus V4 GX-1000 support high-end graphics cards?
Yes, this unit provides 1000 watts of power, making it suitable for demanding graphics cards. It is rated for high-end gaming and workstation builds. The fully modular design helps manage cable clutter in systems with multiple GPUs. This capacity ensures stable power delivery for top-tier components without unnecessary bulk.
What is the difference in modularity between these two power supplies?
The Seasonic Focus V4 GX-1000 is fully modular, allowing you to connect only the cables you need. The Seasonic 300W Flex ATX Gold data does not specify its modularity status. You should check the manual for the Flex unit to confirm if cables are fixed or detachable. Modularity helps with airflow and cable management in tight spaces.
Can I use the 300W Flex unit for a gaming PC?
It is not recommended for typical gaming PCs, as it only delivers 300 watts. This output is best for compact low-power industrial systems or basic office builds. Gaming systems usually require significantly more power for the CPU and GPU. The Focus V4 GX-1000 is the appropriate choice for gaming due to its 1000-watt capacity.
How do the physical dimensions compare between the Flex and Focus models?
The Focus V4 GX-1000 measures 5.9 inches wide, 3.4 inches high, and 5.5 inches long. The Flex ATX unit is smaller to fit compact cases, though exact dimensions are not listed in the provided data. The Flex model weighs less due to its lower power output and smaller build. You must measure your case clearance carefully for the Flex unit.
Do both units feature active power factor correction?
The Seasonic 300W Flex ATX Gold explicitly features active PFC for improved power efficiency. The Focus V4 GX-1000 data does not list its PFC type. Most modern high-efficiency units include active PFC, but you should verify this in the Focus manual. Active PFC helps stabilize input voltage and reduces harmonic distortion.
Which PSU is better for a mini-ITX build?
The Seasonic 300W Flex ATX Gold is better for mini-ITX builds due to its compact form factor. It fits where standard ATX units cannot. The Focus V4 GX-1000 is larger and designed for standard ATX cases. If your mini-ITX case supports Flex ATX, the 300W unit is the practical choice for low-power systems.