When building or upgrading a desktop computer, one of the crucial components to consider is the power supply unit (PSU). Among the most common types of power supplies are SFX (Small Form Factor) and ATX (Advanced Technology eXtended). Understanding the differences between these two can significantly influence your build’s performance, aesthetics, and compatibility. In this article, we’ll explore the primary differences between SFX and ATX power supplies, delving into their size, power output, cooling mechanisms, and intended use cases.
Size and Form Factor
The most noticeable contrast between SFX and ATX power supplies is their size. SFX power supplies are designed for small form factor (SFF) cases, making them ideal for compact builds.
| Power Supply | Dimensions (L x W x H) |
|---|---|
| ATX | 5.9 x 5.5 x 3.4 inches |
| SFX | 4.9 x 2.5 x 3.9 inches |
The smaller dimensions of SFX units make them the preferred choice for mini-ITX and other SFF cases. However, the compact size can pose challenges in terms of cooling and power output.
Power Output
When it comes to power delivery, ATX power supplies generally have higher wattage ratings. This makes them suitable for high-performance builds that require more power for components like high-end graphics cards, multiple storage devices, and overclocked CPUs.
SFX power supplies, while increasingly capable, often have lower wattage ratings. Still, advancements in technology have led to the development of high-wattage SFX power supplies, now capable of powering fairly demanding builds.
Comparative Table of Power Output
| PSU Type | Typical Wattage Range |
|---|---|
| ATX | 450W to 1600W+ |
| SFX | 300W to 800W+ |
This wattage difference makes ATX power supplies more versatile for a wider range of systems, particularly those requiring substantial power.
Cooling Mechanisms
SFX and ATX power supplies often employ different cooling strategies, reflective of their design and power output needs.
- ATX Power Supplies: Typically feature larger cooling fans (120mm or 140mm), which facilitate better airflow at lower RPMs, resulting in quieter operation while effectively dissipating heat.
- SFX Power Supplies: Smaller cases mean reduced space for cooling solutions. These units often feature smaller fans (80mm or 92mm) which may need to spin faster to provide adequate cooling, potentially resulting in more noise.
The compact nature of SFX power supplies can also lead to denser placement of components, which requires efficient heat management strategies to maintain operating temperatures.
Intended Use Cases
The intended use cases for SFX and ATX power supplies significantly differ due to their form factors and power capabilities.
- ATX Power Supplies: Ideal for standard desktop cases, gaming PCs, workstations, and enthusiast builds where space and power are less of an issue. They are particularly suitable for systems with high power demands such as multiple GPUs, overclocking, and extensive peripheral usage.
- SFX Power Supplies: Designed for compact and portable builds. They are often used in mini-ITX cases, HTPCs (Home Theater PCs), and other small form-factor systems where space is at a premium and a lower power demand can be managed.
The choice between SFX and ATX often boils down to the specific requirements and constraints of the build, including case compatibility, power needs, and personal preferences regarding noise and aesthetics.
Modular vs. Non-Modular
Both SFX and ATX power supplies are available in modular, semi-modular, and non-modular configurations. Modular power supplies allow users to connect only the cables they need, reducing cable clutter and improving airflow.
While modularity is beneficial for all types of builds, it is especially advantageous in small form factor cases where space is limited.
Summary
In conclusion, SFX and ATX power supplies cater to different needs and build types. ATX power supplies are general-purpose, versatile units capable of delivering high wattage with excellent cooling solutions, suitable for spacious cases and high-performance systems. On the other hand, SFX power supplies are compact, making them perfect for small form factor cases and builds where space and size are major considerations. Your choice between the two should be guided by your specific requirements, including power demands, case size, and desired system performance.