ATX vs. EATX Motherboards: Key Differences Every PC Builder Must Know

When building or upgrading a PC, one of the most critical decisions every PC builder faces is choosing the right motherboard size. The motherboard determines not only the performance potential of your build but also what components and features you can include. Among the most popular choices are ATX and EATX motherboards — two form factors that seem similar but differ significantly in size, expandability, and cost.

This article provides an in-depth comparison of ATX vs. EATX motherboards, helping you understand their structure, benefits, drawbacks, and how to choose the right one for your specific PC build.

Confused about whether to choose an ATX or EATX motherboard for your next PC build? Eureka Technical Q&A connects you with hardware experts who can explain form factor differences, compatibility issues, and performance considerations—helping you make smarter, faster decisions when building or upgrading your PC.

What Is an ATX Motherboard?

ATX stands for Advanced Technology eXtended, a standard motherboard size introduced by Intel in the mid-1990s. It has since become the most common motherboard form factor used in gaming PCs, workstations, and general desktop builds.

The ATX motherboard typically measures 12 x 9.6 inches (305 x 244 mm). It offers a balanced design with enough room for essential components like CPUs, RAM, and PCIe expansion slots, while still fitting comfortably inside most mid-tower PC cases.

What Is an EATX Motherboard?

EATX, or Extended ATX, is essentially a larger version of the standard ATX motherboard. Measuring 12 x 13 inches (305 x 330 mm), EATX motherboards provide additional physical space, allowing manufacturers to include extra features such as more RAM slots, additional PCIe lanes, and advanced power delivery systems.

These boards are commonly used in high-end gaming setups, professional workstations, and enthusiast-level builds that require support for multiple GPUs, extensive storage, and enhanced cooling options.

ATX vs. EATX Motherboards: Key Differences Explained

While ATX and EATX motherboards share many design features, several critical differences set them apart — and these should directly influence your purchasing decision.

1. Size and Physical Dimensions

• ATX: 12 x 9.6 inches (305 x 244 mm)
• EATX: 12 x 13 inches (305 x 330 mm)

EATX motherboards are wider, meaning they take up more space inside the case. This extra width accommodates more components but requires larger full-tower or specially designed EATX-compatible cases.

2. Expansion Slots and RAM Capacity

ATX motherboards typically offer:

• 4 RAM slots (supporting up to 128GB in most cases)
• 3 to 4 PCIe slots (for GPUs, sound cards, etc.)

EATX motherboards may include:

• 6 to 8 RAM slots (supporting up to 256GB or more)
• 4 to 8 PCIe slots for GPUs, capture cards, and other peripherals

This makes EATX ideal for demanding users like content creators, engineers, or gamers running multiple GPUs or RAID storage systems.

3. Case Compatibility

Choosing between ATX and EATX motherboards heavily depends on your PC case.

• ATX motherboards fit comfortably in mid-tower and full-tower cases.
• EATX motherboards require larger full-tower cases specifically designed for EATX or extended sizes.

Always check the case specifications to ensure it supports EATX if you opt for that form factor.

4. Price Difference

Generally, EATX motherboards are more expensive than ATX boards due to their enhanced feature set and larger size. The additional PCIe lanes, RAM support, advanced cooling headers, and reinforced power delivery systems all add to the manufacturing cost.

ATX motherboards are more budget-friendly and sufficient for most users unless high-end, multi-component configurations are needed.

5. Typical Usage Scenarios

Motherboard	Best for	Why
ATX	Gamers, everyday users, moderate PC builds	Great balance of size, features, and price
EATX	Enthusiasts, content creators, workstations	Advanced features, multiple GPUs, large memory support

Pros and Cons of ATX Motherboards

Pros:

• Affordable pricing
• Widely compatible with most PC cases
• Balanced features for gaming and general use

Cons:

• Limited RAM slots (usually 4)
• Fewer PCIe lanes compared to EATX

Pros and Cons of EATX Motherboards

Pros:

• Maximum expansion potential
• Ideal for high-end GPUs, storage, and RAM
• Advanced features like superior VRMs and cooling support

Cons:

• Larger size requires bigger cases
• Higher price point
• May leave empty space unused for simpler builds

Which Motherboard Should You Choose?

Your choice between ATX and EATX motherboards comes down to your specific needs, budget, and case compatibility.

Choose ATX if:

• You are building a gaming PC or standard workstation.
• You want a cost-effective solution.
• You’re using a mid-tower case.
• You don’t need more than one or two GPUs or extreme RAM capacity.

Choose EATX if:

• You require a workstation or enthusiast build.
• You plan to use multiple GPUs.
• You want support for 128GB+ RAM.
• You’re using a large full-tower case.
• Budget is not a major concern.

Conclusion

Both ATX and EATX motherboards offer excellent performance and are suited for different kinds of PC builders. ATX is the go-to choice for most gamers, home users, and general builds due to its affordability, standard size, and balanced features. EATX, on the other hand, is tailored for advanced users who demand maximum expandability, multiple GPUs, and the highest level of performance.

When deciding between ATX vs. EATX, always consider your usage scenario, the components you plan to use, and whether your PC case can accommodate the size of your motherboard.

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