Hi there! Choosing between ATX vs EATX motherboards for your new PC build? As an experienced system builder, let me walk you through the key differences between these two popular form factors. I‘ll explain everything you need to know about sizes, features, performance, ideal use cases, and more. You‘ll see why ATX remains the gold standard for most desktops, while costly EATX boards appeal primarily to high-end gaming and professional workstation builds. Let‘s dive in!
A Brief History of ATX and EATX
First, a quick history lesson. The ATX form factor was introduced by Intel in 1995 as an evolution of earlier standards like AT and Baby AT. ATX added new features like front panel IO ports, better airflow, and cable management. It also defined common mounting points for efficient case design.
ATX was rapidly adopted during the late 90s PC boom. It struck the right balance of expansion capabilities in a reasonably compact footprint. ATX remains the standard for consumer desktop boards from all manufacturers to this day.
Extended ATX or EATX arrived in 1997 as a variant of ATX designed for high-end systems. EATX added more PCI, RAM, and CPU slots to accommodate enterprise gear and enthusiast machines. However, EATX never saw mass adoption due to its larger size. Today it occupies a niche for extreme workstation and gaming rigs.
Now that we‘ve covered a bit of motherboard history, let‘s explore the ATX and EATX differences in more detail.
Physical Size Comparison
The most noticeable difference between ATX and EATX is the larger dimensions of EATX boards:
ATX size: 12 x 9.6 inches (305 x 244 mm)
EATX size: 12 x 13 inches (305 x 330 mm)
As you can see, ATX boards are a compact 12 inches long but max out at 9.6 inches wide. EATX keeps the 12-inch length but extends the width to a full 13 inches.
This 4 extra inches of width allows EATX boards to cram in more slots and features. However, it also requires a larger EATX-compatible PC case. More on that later.
Here‘s a visual comparison of the two form factors side by side:
Just by looking at the different dimensions, you can already see how EATX boards offer more room for add-in cards, memory banks, and other components.
Expansion Slot Comparison
Let‘s move on to expansion slots, which allow you to add components like video cards and RAID controllers. This is where EATX motherboards really flex their muscles.
ATX boards come equipped with 4 to 7 expansion slots in most cases. High-end models may max out at 7 full-length PCI or PCIe slots. This provides solid expandability for the majority of home and gaming PCs.
EATX motherboards blow the doors off with up to 8 or more expansion slots. Extreme models like the ASUS ROG Zenith II Extreme Alpha even pack in a whopping eight PCIe 4.0 x16 slots, ready for quad or octo GPU configs.
Clearly, EATX delivers vastly more expansion potential. Here‘s a visual overview of how the slots differ:
Gamers running triple-SLI or Crossfire setups with multiple graphics cards will benefit greatly from EATX boards. So will professional users needing to connect many PCIe storage drives and RAID controllers.
But for mainstream PCs, ATX boards provide ample room for a single powerful video card and maybe an extra PCIe SSD.
Memory Support Comparison
Another area where EATX boards excel is memory support. The extra surface area allows EATX boards to cram in more DIMM slots for RAM modules.
Most ATX boards come with 4 DIMM slots, supporting up to 64GB of RAM. High-capacity modules like 16GB DDR4 DIMMs are becoming more affordable, so 64GB is sufficient for nearly all home builds.
Meanwhile, premium EATX boards often boast 8 DIMM slots, enabling insane amounts of memory. With 8 slots, you can configure up to 128GB by populating each slot with 16GB DIMMs.
Some execution-oriented workstation builds for video editing, 3D rendering, data science, and programming really come alive with oodles of RAM. EATX paves the way for massive memory up to 256GB or even 512GB!
Here‘s a quick visual guide to the DIMM slots:
However, keep in mind that high density RAM configurations require a compatible processor. Intel‘s Xeon server chips support 8-channel memory. But consumer chips like the i7-12700K are often 4 channel, so they won‘t fully utilize 8 DIMM slots.
Nevertheless, if you have an appetite for capacity, EATX delivers!
CPU Support Differences
When it comes to processor support, EATX also grants more flexibility. The abundant space allows motherboard makers to include multiple CPU sockets on EATX boards.
ATX boards exclusively utilize a single socket for one processor. This is absolutely adequate for most home PCs and gaming rigs.
Meanwhile, premium EATX models may offer:
- Dual LGA sockets for installing two Intel Xeon server CPUs
- Multiple sockets for multi-core AMD Epyc datacenter chips
Dual and quad socket configurations provide tremendous computing horsepower for 3D rendering, video editing, simulations, artificial intelligence, and other demanding tasks.
For instance, the ASUS ESC4000A-E10 server board below supports up to four AMD Epyc 7002 series processors for an incredible 128 total cores / 256 threads!
Very few home users and gamers need that level of parallel processing power. But it demonstrates the capabilities unlocked by EATX boards.
Ideal Use Cases for ATX and EATX
Given the drastically different features and pricing, what are the ideal use cases for ATX vs. EATX motherboards?
ATX boards are perfect for:
- Mainstream home and office PCs
- Budget and mid-range gaming rigs
- Compact Micro ATX and Mini ITX case builds
- Basic workstations for office users
EATX boards excel in these scenarios:
- High-end gaming systems and enthusiast PCs
- Workstations for video editing, 3D rendering, AI, engineering
- Servers that need lots of drive bays and PCIe slots
- Datacenter builds leveraging dual Xeon or Epyc CPUs
- Custom showpiece builds aimed at maxing out capacity
ATX hits the sweet spot for 90% of typical users. But EATX appeals to folks pursuing no-compromise workstations and gaming rigs with customized liquid cooling, multiple GPUs, tons of flash storage, and other elite hardware.
Now that we‘ve compared the specs, let‘s examine some real-world performance differences.
Real-World Performance Considerations
In terms of raw performance, EATX does NOT inherently outpace ATX given similar core components. For example, take two boards with the same Intel Core i9-13900K processor, RTX 4090 graphics card, and high-speed DDR5 RAM. You‘ll see virtually identical gaming frame rates and application benchmarks on both EATX and ATX.
However, EATX enables you to push performance much further through expansion:
Populating all 8 DIMM slots with high-speed RAM aids compute-intensive workloads.
Running triple RTX 3090 cards in NVLink SLI produces drastically higher rendering and gaming FPS than a single GPU.
A dual Intel Xeon setup provides far more multi-threaded horsepower.
So the main performance advantage of EATX lies in the headroom to add more high-end hardware like GPUs, RAM, and PCIe storage down the line.
AnandTech recently benchmarked the ASUS ROG Maximus Z690 Extreme EATX board with an Intel Core i9-12900K Alder Lake CPU and DDR5-6000 RAM. It kept pace with more affordable ATX Z690 options thanks to the same processor and memory:
So bottom line, don‘t expect an immediate performance gain from EATX alone. Focus first on your CPU, GPU, RAM, and storage selection when aiming for max speed.
Comparing ATX and EATX Pricing
Another major difference between ATX and EATX lies in the pricing. EATX motherboards command a significant price premium due to:
- More high-speed PCIe slots and switches
- Beefier VRMs to supply stable power for multi-GPU
- Extra layers and complex routing for trace paths
- Additional materials needed for larger boards
- Lower production volumes compared to ATX
For example, let‘s compare two high-end X670 boards from MSI for AMD‘s Ryzen 7000 CPUs:
- MSI MEG X670E ACE MAX: $699 EATX board 
- MSI MEG X670E ACE: $599 ATX board with similar feature set 
As you can see, the EATX version carries a $100 price premium, or about 17% more. You‘ll typically pay 25-50% more for an EATX board versus a comparable ATX model.
Make sure to factor in the additional costs when deciding between ATX and EATX. You‘ll also need a larger EATX-ready case which adds to the budget.
Finding the Right ATX or EATX Board
If you‘ve weighed the trade-offs and decided on a form factor, here are some tips for picking the perfect ATX or EATX motherboard:
ATX Board Shopping Tips:
- For Intel Alder Lake, look for Z690, H670, or B660 chipsets
- For AMD Ryzen, consider X670, B650, or X570 boards
- Ensure the socket (LGA1700, AM5, AM4) matches your CPU
- Check that memory support matches your DDR5 or DDR4 RAM
- Prioritize connectivity like M.2 slots, USB ports, WiFi 6E
- Gaming-focused boards boast premium VRMs, audio, and RGB lighting
EATX Board Shopping Tips:
- Focus on high-end X699 and WRX80 chipsets for Intel and AMD
- Requirements like ECC memory support for Xeon Pros
- Look for boards with 7 or 8 x16 PCIe slots for multi-GPU
- Ensure adequate PCIe lane allocation for numerous devices
- Server-oriented features like IPMI and remote management
- Beefy heatsinks, power phases, capacitors for stability
It pays to read reviews on trusted sites like Tom‘s Hardware and watch YouTube board roundups to make the best selection.
The Bottom Line
To wrap up, here are my closing thoughts on choosing ATX vs EATX for your next PC:
ATX delivers the right balance of expandability, features, and affordability for most desktop needs.
EATX shines for no-compromise workstations and gaming rigs when you need maximum capacity and expansion.
Carefully consider your performance requirements, budget, and case size when deciding on form factors.
Focus on choosing the right CPU, GPU, RAM, and storage first, then pick a board to match.
Thanks for sticking with me on this journey comparing ATX and EATX motherboards! Let me know if you have any other questions. I‘m always happy to help a fellow PC builder select the ideal components for their system. Best of luck with your new rig!