At PremiumBuilds, we spend a considerable amount of time researching and comparing a vast array of options for our custom build guides and component roundups to give you as many choices as possible, no matter your budget or build focus. Today, we’re going to dive into a bit more detail on the specific form factors our builds and recommendations revolve around and compare them so you can get a better idea of which is right for you and why. More specifically, we’ll explain the most common motherboard form factors (which translates to power supply (such as SFX) and case form factors as well), their histories, why you might pick each one, and their respective pros and cons. But first…
A Rough Outline
Motherboards earn their name in that they’re responsible for the communication between whatever parts you decide to purchase and install in your shiny new case; they make sure everything plays nice and works together properly! For new builders or those simply unclear on how PCs work, microelectronics share many similarities, though rudimentary, with the human nervous system. You can sort of look at the embedded circuit traces as bundles of nerve fibers (axons), the various onboard and discrete components as neurons and neural circuits, and the connectors that tie them together as synapses. Just like the nervous system carries electrochemical impulses between your brain and body, electricity shoots through the motherboard between your CPU and the rest of your components. Over time, desktop PC motherboards became standardized and have developed into the most common designs we see on the market today.
The first, and by far the most popular, standard logic board and power supply design we have today is ATX. ATX (Advanced Technology eXtended) is the successor to the IBM Baby AT form factor of the mid-to-late-80s, which was itself a more compact successor to the original IBM AT. The main reason for the advent of ATX was the fact that CPU coolers were getting considerably more substantial, and they began to block the clearance of full-length PCI and ISA cards on Baby AT boards. As a response, Intel developed ATX in 1995 to further improve upon space optimization and overall hardware interchangeability with a highly scalable layout that has, ever since, lent itself well across all of the current mainstream options: ExtendedATX, ATX, microATX, and Mini-ITX.
Most of you probably have ATX machines, and the image that pops into your head when you hear the word “PC” is likely of an ATX sized build as well. At this stage, ATX is typically the most reasonably priced and plentiful form factor for motherboards from any manufacturer, likely due to the nearly unlimited possibilities of building in an ATX system, as well as the relative ease in doing so. PC enclosures nowadays, even most mid-towers, have almost no hardware restrictions and are also capable of accommodating completely custom liquid cooling loops. Meaning, ATX (and EATX) guarantee the ability to build the absolute most powerful consumer desktops possible, with support for massive power supplies, multiple full-length GPUs, the largest heat sinks, and plenty of fans, or reservoirs, cooling blocks, radiators, and tubing. If you’re inexperienced with building computers, ATX is the most accessible entry-point and offers the best configuration flexibility. EATX is just a slightly larger variant of ATX where you’ll usually find the best VRMs (voltage regulator modules), most connectivity options, the beefiest build quality, highest prices, and slightly worse case compatibility.
- Easiest to build in.
- Best hardware compatibility/flexibility (least amount of research required).
- Best liquid cooling support.
- Has the most motherboard and case options available.
- Highest-performance, most features, and best build quality with EATX.
- Largest (and heaviest) of all the form factors.
- Potentially wasted space with air-cooled, single GPU builds.
- Possibly too many options to choose from.
- Most expensive with EATX.
If you’ve decided your next build is going to be a standard ATX, check out our guide to some of the best mid-tower ATX cases on the market!
Next, we have, at least recently, the least popular form factor: microATX (mATX). Just a couple of years after the release of ATX, in 1997, Intel developed the mATX form factor. mATX is virtually identical to ATX, just slightly shorter, and with fewer expansion slots. Otherwise, you’ll typically find the same chipsets, comparable VRMs and connectivity, connectivity options, and features on mATX motherboards as most full-sized ATX options.
This form factor is supported by nearly all full-tower and mid-tower enclosures by swapping a few standoff screws, with even more options for mATX specific micro-tower cases available from almost every major manufacturer on the market. For the most part, mATX specific micro-towers still retain most of the flexibility, ease of use, and hardware compatibility as even some full-tower ATX cases. You can very often still use most full-sized ATX power supplies, bulky dual-tower heatsinks, plenty of case fans, and a majority of full-length triple-slot GPUs. However, you might be restricted to closed-loop AIO liquid coolers instead of fully custom open-loop liquid cooling with multiple radiators and a reservoir unless you’re reasonably experienced and know how to select and install hardware that will fit properly.
The major downside to building mATX systems is the fact that you usually don’t have nearly as many motherboard options to choose from. Manufacturers develop significantly less high-end mATX motherboards for Intel and AMD chipsets nowadays than both ATX and mini-ITX, especially considering the massive spike in popularity for SFF (small form factor) PCs in the enthusiast market over the past few years. For example, there is still only one mATX motherboard for AMD’s X570 chipset, and it wasn’t until the release of the B550 chipset that we saw newer and significantly more robust offerings for Ryzen Zen 2 CPU’s. mATX shouldn’t necessarily be on the way out any time soon, but you do need to keep this in mind if your goal is to build a high-end compact PC. Regardless, mATX is an excellent choice for builders potentially looking for something smaller than a full or mid-tower build, but who may not want to deal with some of the hassle associated with SFFPCs like extensive compatibility research, and a trickier build process.
- Compatible with full and mid-tower cases, with many specific micro-tower options available as well.
- About as easy to build in as standard ATX.
- Smaller footprint than ATX.
- Minimal hardware compatibility restrictions (supports most full-length ATX power supplies and triple-slot GPUs).
- Less wasted space for air-cooled, single GPU builds.
- Significantly worse availability/support from motherboard manufacturers (much less popular).
- Worse liquid cooling support than full and mid-tower ATX cases.
- Less well-designed specific micro-tower cases from case manufacturers.
- Nowhere near as compact or space-optimized as SFF systems.
If you find yourself drawn to a microATX system, take a look at our guide to the most compact micro-tower cases out there!
For the final form factor of today: Mini-ITX (Mini Information Technology eXtended). In 2001, a company called VIA Technologies developed and released the mini-ITX form factor aimed at set-top boxes (such as cable and satellite boxes) and industrial SFFPCs (enterprise computers typically installed on the back of displays). At first, mini-ITX motherboards exclusively had onboard or embedded components, e.g., CPUs and system memory were soldered directly onto the board. Enthusiast builders, however, were intrigued by the prospect of ultra-compact, low-noise, and power-efficient systems, where they started experimenting with wild case mods by building them into toys, instruments, humidors, and even a 1960s toaster! Soon after, Intel released a socketed version for their LGA 775 chipset, and their popularity has been steadily climbing ever since.
The massive popularity of mini-ITX SFF PCs is thanks, by and large, to the continuing advancement of PC hardware overall. Companies are developing smaller, more powerful, and highly efficient components that have started to lead builders to question whether they really need to take up so much desk space with even compact micro-tower builds. As a response to the interest in and demand for tiny powerhouse computers, we’ve seen many crowd-funded designs launch very successful new start-up companies with exceptionally well-made and highly-rated cases. For example, the LOUQE Ghost S1 and the NCASE M1, highly coveted SFF enclosures with amazing build quality, space optimization, and hardware support, are both insanely popular and quite difficult to get ahold of considering how quickly they sell out of each new production run. Builders could potentially wait several months even to receive their purchases in the mail!
Despite how impressive mini-ITX platforms have become, there are some definite caveats. When building in such tight quarters as with many of the best SFF cases, hardware compatibility is pretty restrictive. It requires thorough research to determine what parts you can actually install. For example, you’re mostly limited to low-profile memory kits, and specific CPU air-coolers depending on what can fit in your chosen case. You’re also going to need an SFX power supply, as the vast majority of SFF cases simply cannot accommodate full-sized ATX power supplies. Thermal performance is also a potential issue with high-end components. You’ll likely need to invest a significant amount of research, time, and money to figure out how to keep your particular system as cool as possible, especially for air-cooling with limited support for case fans. If you’re set on building in a shoebox, keep this in mind when selecting your hardware. Furthermore, mini-ITX cases and components are usually much more expensive than all but the top-tier enthusiast-class EATX motherboards for each chipset, and also tend to go through many iterations over time.
- The smallest mainstream form factor on the market.
- Many options capable of supporting even the most powerful CPU/GPU combinations.
- Several options with fantastic build quality and overall design.
- Extreme portability.
- Mini-ITX specific cases and parts are significantly more expensive than all but the most premium EATX enthusiast options.
- Limited availability and long wait-times for premium offerings.
- Severely restricted hardware compatibility (requires extensive research).
- Limited thermal performance due to restricted liquid and air-cooling support.
- Potential buyers remorse if you purchase something that receives a new and improved version shortly after.
If you wish to truly test the limits of the smallest form factor, head over to our list of the best mini-ITX cases that can accommodate a full-sized GPU!
With how much PC hardware has advanced over the past couple of decades, builders have more choice than ever when it comes to the size and performance of their next rig. Whether it be a monstrous multi-GPU build with completely custom liquid cooling, your everyday full-sized gaming/workstation PC, or a miniature nuclear reactor. Also, due to recent global events, more people than ever have found themselves interested in starting their PC building journey, and such freedom in the sort of computer you want to build is a welcome sight indeed. Now we only have to wonder how long it will be before we have desktop-level performance in the palms of our hands 😊!
What form factor do you think you’ll be building next? Do you now have a better understanding of the differences between each one, and which is best for you? Let us know your thoughts in the comments below, and, as always, thanks for reading!