Are all PSU’s the same size?
In today’s computer hardware world, Power Supply Units (PSUs) play a crucial role in providing the necessary power to components, ensuring they run smoothly and efficiently. With so many options available in the market, it’s easy to wonder: Are all PSU’s the same size? Not quite, and we’ll explore the reasons why in this article.
Direct Answer: No, not all PSU’s are the same size
While most modern PSUs share a similar overall shape and design, there are significant differences in their dimensions, connectors, and compliance requirements, which set them apart. In fact, the ATX (Advanced Technology eXtended) standard, the most widely adopted PSU form factor, has undergone several revisions, leading to various size options:
ATX Standard Revision and PSU Sizes
| Revision | Length (mm) | Width (mm) | Height (mm) |
|---|---|---|---|
| ATX 1.0 (original) | 185 | 140 | 40 |
| ATX 2.0 | 185 | 140 | 42 |
| ATX 2.2 | 180 | 140 | 42 |
| ATX 3.0 | 190 | 140 | 44 |
Table 1: ATX standard revision and PSU sizes (length, width, and height)
Key Takeaway: Although ATX is the most popular form factor, the standard has undergone changes, leading to variations in size. A standard ATX PSU measures approximately 180-190 mm in length, 140 mm in width, and 42-44 mm in height.
Other PSU Form Factors and their Sizes
| Form Factor | Length (mm) | Width (mm) | Height (mm) |
|---|---|---|---|
| Micro-ATX | 170 | 120 | 38 |
| Mini-ITX | 160 | 60 | 35 |
| Pico-ITX | 122 | 60 | 30 |
| 5.25-inch Bay (Legacy) | 190 | 140 | 30 |
Table 2: Other PSU form factors and their sizes
Key Takeaway: Other form factors like Micro-ATX, Mini-ITX, Pico-ITX, and the older 5.25-inch bay require specific PSU sizes, catering to smaller or specialized systems.
PSU Connectors: The Other Factor
In addition to physical size, PSU connectors also play a significant role. ATX-specific connectors include:
- ATX12V main power connector
- 4-pin +4-pin ground
- 6-pin / 8-pin +12V aux power
- SATA power (3-pin)
S-expression, Mini-PCIe, and other specialized connectors are also present in certain PSUs, catering to specific computer systems.
Key Takeaway: PSUs can have varying connector configurations, depending on the specific system requirements or compatibility needs.
PSU Compliance Requirements: What You Need to Know
In addition to size and connectors, PSUs must adhere to various compliance requirements, including:
- 80 PLUS certification (Gold, Silver, Bronze, and Titanium) for energy efficiency
- Electromagnetic Compatibility (EMC) for reduced interference with other devices
- FCC Part 15 for US regulatory compliance
- CE, RoHS, and WEEE for EU regulatory compliance
Key Takeaway: PSUs must comply with various regulations and standards, ensuring safe and efficient operation, as well as reduced environmental impact.
Conclusion
Are all PSU’s the same size? No, due to the diverse range of form factors, connector configurations, and compliance requirements. While ATX remains the most widely adopted form factor, smaller and specialized formats exist, catering to various system and application needs. When choosing a PSU, it’s essential to consider the specific requirements of your system or application to ensure compatibility, reliability, and efficiency.
Recommended Reading: For a more detailed understanding of PSU selection and compatibility, we recommend exploring online resources, such as the ATX standard documentation and PSU vendor specifications.