Motherboard Form Factor Comparison: Micro-ATX vs Mini-ITX vs ATX

Motherboards nowadays come in a variety of sizes and form factors. But, the most common form factors are Micro-ATX, ATX, and Mini-ITX. Whether you are building an ordinary PC for daily browsing or a High-End Gaming PC, a motherboard will always remain a crucial piece of hardware, and picking which one to buy can seem like a daunting task.

In the following article, we will explain how a specific motherboard type differs from the others; and eventually, we will aim to give you a better sense of which form-factor motherboard is the best fit for your build.

To provide you with a better understanding of the differences, we are going to categorize the overall comparison between the motherboards in terms of the following factors:

1. Size & Case Compatibility,
2. Motherboard Compatibility,
3. Features,
4. The Pros and Cons. 

To understand which motherboard is the best selection for you, let’s start!

Before talking about the size, we first need to understand what form factor means? It describes the specifications of a motherboard such as size, dimensions, PSU type, location of the mounting holes, number of ports, and more. 

The standard dimensions of different motherboards are as follows:

• Micro-ATX – 24.4 cm x 24.4 cm.
• Mini-ITX – 17 cm x 17 cm.
• ATX – 30.5 cm x 24.4 cm.

The main difference between these three form factors is their physical dimensions. As you can see, ATX is the largest of them all, then there’s the Micro-ATX which has the same width as the ATX but is 20 percent shorter in length. Mini-ITX is the smallest one, which was the main reason for producing the ITX design in the first place. 

The width of a standard ATX proves a point of advantage as it allows them to include more PCIe lanes. This makes them better suited for multiple-GPUs, or for consumers who plan on utilizing multiple PCIe devices.

On the other hand, the Mini-ITX is the smallest in both height and width and can only feature a single PCIe lane. However, their advantage is also their size as they can fit in small form factor cases — which was the reason they came into existence in the first place.

Now talking about the Case Compatibility,

• A mini-tower case (primarily made for ATX motherboards) will support Micro-ATX and Mini-ITX boards because these cases provide standardized mounting holes for all three form factors. But, in some places, Mini-ITX support is sacrificed for some reason. Therefore, you should check compatibility first. 
• A micro-ATX board can fit inside every case that backs ATX boards. They are of the same width and have the same mounting hole placements as ATX boards.
• ATX-boards can fit inside mid-tower and full-tower cases. Some micro-ATX cases support ATX motherboards. So, if you want to accommodate an ATX board inside a micro-ATX case, it is possible, but you should do your research first.
• Most often, a mini-ITX (case) is compatible only with the mini-ITX standard. There are very few options where a mini-ITX can fit some other board.

The next topic is Motherboard Compatibility. Talking about the memory (RAM) capacity that each of the form factors can provide. Both standard ATX and micro-ATX hold 4 RAM slots, compared to the mini-ITX, which only has 2 RAM slots. One point to remember is that a mini-ITX can only host a maximum of 2 x 16GB memory sticks, meaning a total of 32GB of RAM. However, the standard ATX and micro-ATX are certainly powerful in this regard as they can provide double what a mini-ITX offers. 

Another consideration is the number of PCIe slots that each form factor offers. PCIe slots are a necessity for Gaming Builds and High-End setups. Standard ATX usually has around 7 PCIe slots, and the micro-ATX usually comes with 4 PCIe slots, still sufficient for many situations; but, the mini-ITX only comes with 1 PCIe slot. 

Stressing on the price comparison, it is surprising that mini-ITX is the second most expensive motherboard, leaving micro-ATX as the affordable choice and standard ATX as the premium choice.

The standard ATX is the most costly due to its compatibility, size, and overall performance.

Micro-ATX boards possess some prominent upper mid-range features like high-speed memory, dual M.2 slots, multiple PCIe slots, rich I/O connectivity, and USB Type-C support.

With mini-ITX, dimensions are the biggest differentiator. That is why mini-ITX boards do not have more RAM slots, PCIe slots, or more than two M.2 slots. Nonetheless, motherboard manufacturers continue to pack more and more features into mini-ITX boards as technology advances. Thanks to the innovations such as more powerful RAM sticks, faster storage technologies, Wi-Fi 6, lots of rear I/O connectivity, and compact VRMs, you can still build a decent PC based on a Mini-ITX motherboard. But at the end of the day, a small form factor means compromising on some features for sure.

Finally, the ATX form factor is most widespread in the motherboard market. The thing about ATX is that you can find a flagship motherboard that packs every single feature out there. Further, ATX boards serve every price point. They also come with a wide range of specification gaps and offer something for everyone in the market, no matter your requirements.

Be it micro-ATX, Mini-ITX, or standard ATX, every form factor has its unique pros and cons. And in the end, it all comes down to which type of PC you’re looking to build. Below we have stated some of the general pros and cons linked to each form factor.

Micro-ATX: 

Pros: 

• Least Expensive
• Best All-Round Choice
• Best Case Compatibility
• Better RAM capacity compared to Mini-ITX

Cons: 

• Limited PCIe Slots (4 Slots) Compared to Standard ATX (7 Slots)

Mini-ITX: 

Pros: 

• Smallest in Size
• Most Lightweight Option
• Cheaper than Standard ATX

Cons: 

• Maximum RAM Capacity of 32 GB
• Single PCIe Slot
• More Expensive Compared to micro-ATX

ATX: 

Pros: 

• Can Support up to 19 PCIe slots
• High RAM Capacity
• Supports Multiple GPUs
• Supports Overclocking

Cons: 

• Very Expensive
• Large Overall Profile

From the above comparison, it is evident that micro-ATX is the best all-around choice given that it is both smaller than the ATX and also has a decent amount of memory capacity and PCIe slots. 

And practically, ATX is for the users who want to build a monster rig that is capable of handling extensive gaming and high-end work including extreme multi-tasking and mining jobs. While the mini-ITX is for those looking for a small and convenient motherboard suitable for lighter use PCs.

Now you have reached the point in this article where you presumably have a solid understanding of what each form factor has to offer in terms of size, compatibility, and performance. Now it’s time to determine which one to pick. There are some scenarios we are going to talk about which will make things easier for you. 

• If you are thinking of Building a Gaming PC, then there are two points to be clear on first up. Firstly: how powerful should this build be? Almost every video game these days can be run smoothly on a decent CPU and a single graphics card. In this given scenario, we recommend a micro-ATX board for its adequate RAM capacity with the added feature of 4 PCIe slots running together. There are only a few situations where this choice can prove wrong: if you need a greater number of PCIe slots if you have more GPUs for crypto mining or intensive overclocking. 
• The second scenario is that you are planning to Build a Work Computer. A micro-ATX motherboard can do wonders here unless you are doing complex photo and video editing or intense internet browsing with dozens of tabs open at once, in which case you may need an ATX. In our opinion though, you have ample PCIe slots and a good RAM capacity with a micro-ATX.
• Last but not least, if you’re planning for a Home PC setup. If this is the case, then you should consider the design and performance of the three different cards. For instance, if you’re looking to build something slim and stylish then the mini-ITX is the best. It will be expensive but the size and style proves a point. Conversely, if the size is not a concern, then the Micro-ATX is going to be suitable for the job.
• It is worth keeping in midn that the standard ATX is a high-profile motherboard for those looking to use their PC rigorously and push it to its limits. If you plan on doing data mining or have to do some intensive overclocking or want a very high-end gaming machine then this option is definitely worth considering.

In this article, we compared micro-ATX vs Mini-ITX vs ATX motherboards to illustrate the difference between all three form factors and we explained how one differs from the others. 

Whether you are planning to build a high-end gaming rig or an ordinary home PC, it is always a critical decision to choose the right motherboard which best fits your needs.

Hopefully, after reading this article you will have a better idea of what form factor is right for your needs.

Thanks for reading, we hope you found this article informative!