The End of the ATX PC Form Factor

Created by nathan on Oct. 7, 2013, 12:05 a.m. Last post by ahmaddirar 1 year ago.

The standard ATX motherboard form factor has been around for a long time (since 1995!), long enough that its layout doesn't really make any sense anymore. We've tried to kill it in the past, to no avail--Dell was the last BTX holdout--but what may finally kill ATX are its smaller siblings. Smaller motherboards allow for smaller cases with more efficient airflow, while still giving you everything you need for a powerful desktop computer. You lose some PCI expansion slots, but how many of those does the typical PC gamer really need?

Valve is clearly betting on a post-ATX world. Its Steam Machine test units measure 12 inches by 12 inches by 3 inches and use standard desktop parts--including, Valve says, replaceable motherboards, so they're almost certainly microATX or mini-ITX based.

ATX vs. MicroATX vs. Mini-ITX

You're probably already familiar with the standard ATX motherboard layout. After all, it's been in most of the desktop computers you've owned for the last 20 years--unless you bought a lot of Dells last decade. You know how it goes: 12 inches high, 9.6 inches wide, I/O ports on the top of the left edge, CPU in the upper middle, RAM to the right of it (and sometimes to the left). SATA ports on the lower right, expansion slots in the lower left quadrant. A typical ATX motherboard has six to eight SATA ports, four or more RAM slots, and seven or eight expansion slots.

I'd argue that many of those port and slots are unnecessary. You can build a fantastic desktop and never need more than two or three storage drives, or more than one graphics card and a sound card. You really only need two RAM slots, thanks to 8GB DIMMs, so why would you put all that into a case that's four cubic feet in volume?

A smaller case with the parts closer together will actually be easier to cool.

A standard ATX case takes in air in the lower part of the front panel, and exhausts it out the top and upper rear of the case. This provides a consistent airflow, but the problem is that the major heat-producing parts--the CPU, GPU, and drives--are not all in a straight line, and they're far enough apart that it's hard to cool all of them efficiently with just a few fans. Hence the giant wind tunnels you see in enthusiast systems with a half a dozen fans. A smaller case with the parts closer together will, counter-intuitively, actually be easier to cool.

MicroATX boards are generally 9.6 by 9.6 inches--just a few inches shorter than ATX motherboards. They tend to have four RAM slots, a full-sized CPU socket, six or so SATA ports, and four or fewer expansion slots. I'd argue that this is the enthusiast sweet spot these days, rather than ATX. A MicroATX system can accommodate a dual-GPU setup or a single GPU and a discrete sound card. If you want both, you'll have to go to full ATX.

Loyd's latest gaming PC build is on a MicroATX board and case, and he had plenty of room for all the components of a powerful gaming computer. He could even have used a mini-ITX board and case, if he didn't want a discrete internal sound card. I'm in exactly the same boat--if it wasn't for the sound card I use to power my headphones, I could be using a mini-ITX board and case too. But then, I already have my MicroATX case and mobo, so there's no reason for me to side-grade. My Sandy Bridge i5-2500K and Z68 motherboard will last me for another few years easily.

Move to Mini-ITX and you do end up with a few size-based constraints. Mini-ITX boards are 6.7 inches squared, and weren't originally designed for full-sized desktop CPU sockets at all. Thankfully, radder heads prevailed and we've been able to buy Mini-ITX boards with Intel and AMD desktop sockets for half of a decade. Mini-ITX boards with desktop sockets tend to use two full-sized RAM slots, have four SATA ports, and one PCIe x16 slot, although some with the Thin Mini-ITX standard use desktop processors but mobile RAM. Thin Mini-ITX boards often have onboard mini-PCIe and mSATA slots for WiFi cards and mini SSDs, but no x16 PCIe slot. These are usually used for very low-profile situations, like all-in-one computers or point-of-sale machines, and they're not really interesting for gamers.

If I were building a system today, and I was using an external sound card or USB speakers like the Bowers & Wilkins MM-1s, I'd use a mini-ITX board and case. Even a great gaming PC really only needs a mobo, CPU, RAM, one graphics card, an SSD, and a mass storage drive. And an optical drive, if you're fancy. A good mini-ITX case, like the BitFenix Prodigy or Silverstone's Fortress FT03-Mini or Sugo SG-08, can easily accommodate a powerful system and cool it efficiently with just one fan.

Looking for more on specific ATX, MicroATX, and mini-ITX cases? Check out my earlier guides: The Right Case for Your Next PC Build, Part One and Part Two.

What's are People Actually Building?

If smaller form factors were really enough for gaming, wouldn't we see mini-ITX and MicroATX mobos and cases, and full-on small form factor gaming rigs, increasing in popularity?

Silverstone's TJ08-E MicroATX case.

Yep. I asked Tony Ou at Silverstone if he could share some case sales stats with me. In 2010, three of Silverstone's top ten most-sold cases were MicroATX, one was mini-ITX, and the other six were ATX midtowers or full-towers. In 2011, five of the top ten were MicroATX and two were mini-ITX. Last year, the top five were all MicroATX, the 6th and 7th best-selling cases were Mini-ITX, 8 and 9 were MicroATX again, and only the tenth best-selling case was a full ATX case.

Now, those numbers came with some caveats. Tony said, "MicroATX and Mini-ITX have always been major part of our case business so I don’t think we are an accurate indicator for the overall market," and added that SFF cases are more popular in areas with higher incomes, like "North America, Japan, and some parts of Europe," but that the rest of the world is still ruled by full-sized ATX cases. Still, the fact that small form factor cases were the top nine best selling cases for Silverstone shows that there's real demand.

Small-form-factor gaming rigs like the Alienware X51, iBuyPowerRevolt, Digital Storm Bolt, and Falcon Tiki are becoming quite popular. Those cases take the mini-ITX form factor (or, rarely, design their own motherboards) and compress it even further through the use of clever engineering and riser cards. Because they're even smaller than off-the-shelf small form factor cases, these mini gaming rigs tend to cost more than the DIY versions. But man, the small size is appealing. (It's not online yet, but the November 2013 issue of Maximum PC has a four-way roundup of these mini gaming rigs.)

It looks like Valve's Steam Machine, at least in its prototype configuration, will follow the same basic design as the rigs mentioned above. The prototypes will run full-sized GPUs up to the size of Nvidia's Titan, use hybrid hard drives (presumably the 2.5-inch 1TB Seagate Barracuda XT), have 16GB DDR3/1600, run 450W power supplies, and be 12x12.4x2.9 inches--slightly smaller than the Falcon Northwest Tiki.

New Units of Computing

What about folks who use a desktop for the form factor, not the power? Even if I didn't play games, after all, I'd want a 27-inch monitor, keyboard and mouse in my home office. It's just easier to work with that setup than with a 13-inch laptop.

If that's what you want--desktop input/output without the actual desktop--then you have two options. Either get a laptop and a docking station, or a really small form-factor PC.

Honestly, if I wasn't a gamer, I'd get an ultrabook or ThinkPad (or ThinkPad ultrabook) and a docking station so I could connect a nice 27-inch monitor, keyboard and mouse, speakers, and external drive when I was at my desk.

But if I wanted a little more power, or didn't plan on taking my machine with me, ever I'd get one of the newer, even smaller computers that are coming out, like the Intel Next Unit of Computing (NUC). Unlike even tinier and cheaper mini-boards like the Raspberry Pi, the NUC and similar devices like the Gigabyte Brix II use tiny motherboards with full x86 CPUs--usually soldered-on mobile CPUs--and require you to add your own mobile RAM, mini-PCIe WiFi cards, and mSATA SSDs. They're limited to integrated GPUs, but in the case of the Brix II, for example, that means Intel's top-end integrated Iris Pro graphics, which are powerful enough.

Xi3's Piston, clearly designed as some sort of extra-compact Steam Machine, has sort of been revealed as an even smaller alternative to the more traditional Steam Machines of Valve's Hardware Test.

The Old Ways

Obviously, there are still people for whom an ATX full-tower PC makes sense, but they're not the majority of desktop builders and they haven't been for a long time. Most of us really only need one PCIe x16 slot, a couple of RAM slots, a CPU socket, and a few hard drive mounts. If you need multi-GPU setups, a sound card, a RAID card, or tens of terabytes of space--or all of the above--a full ATX board in a full-sized chassis is what you need. But for the rest of us--even most of us--a small-form-factor PC is plenty.

  • I've been saying this myself for the past two-three years.

    I upgrade my main gaming rig every two years and the last three have been mATX builds. I personally prefer mATX because I still like to use a dedicated sound card but for the majority of people it's not something they need to consider due to the development of onboard sound. Even for someone like myself who likes to overclock and tinker, the options have gotten better with each generation.

    When building my current PC 18 months ago I wanted a board that would not only be the core to my build but allow me to push my CPU to its limits. I had the choice of the flagship ASUS Maximus IV Extreme (ATX) or the ASUS Maximus IV Gene-Z (mATX), I ended up going for the Gene-Z because it had pretty much all the features available on the Extreme but in a smaller form factor and for nearly half the price ($500AUD vs $285AUD). In the end I had no issues pushing my i7 2700K to 5.2GHz with just a Corsair H80 for cooling, had I decided to chase records and pulled out the LN2 I'd have been confident of getting much higher clocks.

    My next upgrade cycle will come in March/April 2014 and you can bet your ass it'll be either an mATX build, if I decide to bring my soundcard over, or an ITX build should I end up going with an external DAC.

  • I guess I'm just a freak. I'm planning to upgrade my Mid-tower antec 900 to a full tower fractal design case. I have a friend with a full tower, and while it is horrendous to move around, the space it provides to work in, and the quietness of the case (due largely to the loads of empty space in it for air to flow), as well as the number of expansion possibilities still draw me to the larger form factor.

  • With a larger case that doesn't have many fans you don't get empty space. You get left with air pockets where airflow is reduced causing turbulence which lowers the effectiveness of your fans and their airflow.

  • @stenchlord: He has a HAF 932(?) so fans are not an issue. lol. The one I'm looking to get is supposed to be good at keeping noise down and still providing good cooling, which is something that I would imagine would be more difficult for most smaller cases assuming the hardware you are putting into them is comparable.

  • I think new micro standard in PSU form factor is needed. U1 server with a loud mini fan is not a solution. I wish there was a mini-itx complimentary PSU that can support a top tier GPU. Shrinking the form factor for a 450W PSU would be good start, modular cable so you can customize cable characteristics. Choice of lengths, and build types. Love to choose flat, round, thin or thick.

  • Heh, "radder heads prevailed", nice one.

  • "Most of us really only need....".

    I'd like to see the data on that.

  • I don't believe you will be able to get rid of ATX boards any time soon, and the reason why is for most of your consumer/casual gamers a Mini-ATX should meet all their needs but for your hard core PC/GAME enthusiasts your 1 PCIe slots and 2-4 SATA ports and 2 DIMM slots that come standard on most Mini-ATX boards is simply not enough.

    The Micro-ATX (Oddly Larger then your Mini-ATX) comes with up to 4 DIMM slots, 1-2 PICe and 2-6 SATA ports will fill the roles that it currently filled by the standard ATX motherboards. The drawback is that most of your Micro-ATX boards are not setup for SLI even if they do have 2 PCIe slots are are to close close together to accept two of the double-width Video Cards. The Micro-ATX boards however will support a single PCIe (Sound/Wireless/Ect) card and a Video Card but it will be a snug fit.

    So if your after SLI in x2, x3 you must use an ATX or Expanded-ATX board, If you want to get above 32GB of RAM (8GB x4 DIMM) you will need to move to an ATX or eATX board. There is still a very valid market for ATX boards and although it is smaller then it was 10+ years ago the form factor is far from dead.

  • @PCTRS80: ...Yes, that's what I said in the column.

    If you need multi-GPU setups, a sound card, a RAID card, or tens of terabytes of space--or all of the above--a full ATX board in a full-sized chassis is what you need. But for the rest of us--even most of us--a small-form-factor PC is plenty.
  • I've been wanting to use the FT03-mini to replace my giant FT02. Thanks for the write-up, this is all the persuading I needed!

  • @nathan: Typo: "so why are would you put all that into a case that's four cubic feet in volume?"

  • The problem i've found when looking to build a Mini-ITX or a Micro-ATX is that there are no decent spec'd motherboards for AMD. Everything is low end for Micro-ATX, and all of the Mini-ITX are only for their APUs, which I don't want to use.

    I just don't see why manufacturers don't create at least a couple higher end Micro-ATX boards for AMD, or some AM3+ Mini-ITX. AMD users want high performing small form factor PCs too.

  • @stenchlord:

    I made the switch from dedicated sound-card (asus xonar essence st) to USB DAC 12 months ago.

    One less thing in your case, and the sound is excellent. Headphone listening is 98% of my usage so 2 channel is actually preferable.

  • @tom032792: I hate the HAF932, the thing is a vacuum for dust and the filters are horrid.

    The only full tower case I'd even consider using is the Silverstone FT-02. Due to its design, it only draws in air from the bottom and vents it all out the top but even then there's no need for such a large build unless you're going to fill it out.

    @simplymortified: Yeah, my issue is I still use my speakers the majority of the time. I live on my own so don't need to worry about waking or bothering other people. We'll see though, by the time I build the next PC my mind might be more easily swayed towards an ITX system.

  • @stenchlord: Yeah, it's not my favorite case, and not the one I plan on getting. However, it's size made it a pleasure to build in, and it's fairly quiet, even under load.

  • @stenchlord: Yeah, Norm uses the FT02 and I used it until I swapped for the microATX TJ08-E. It's a beast of a case, and one of the best air-cooling cases around.

  • @stenchlord:

    While my preference is headphones, my DAC outputs (through a splitter) to a Dayton class D amp and a dedicated headphone amp. The Dayton amp (30+30watts) drives a pair of monitors. 2 channels is fine for me :)

  • Just replaced my huge old ATX machine in a huge Antec case with a Prodigy/ITX. Was super easy to put together - still fit 16GB of RAM, a full-sized PSU, and my aging GeForce 560, all of which are sitting a little prettier in my new half-sized case and i5 Haswell.

    Only downside is that I've seen how well-designed these things are and how much extra room I have left in the case, and now I'm wishing I'd gone with something even smaller than the Prodigy.
  • @nathan: I think you may have been a bit miss leading with your title that the ATX form factor is dead. It maybe less popular then it was but it is far from dead, announcing that it is dead is kind of like announcing that Broadcast Radio or Local TV Stations are dead. They may not be as popular as it was but they are still makeup a huge industry and are going anywhere in the relative future.

    I did a little browsing on some sites (Amazon/NewEgg) and noticed that there are a lot of Mini-ITX and Micro-ATX boards but when i narrowed it down to the INTEL 1150 Socket, I found that ATX motherboard outnumber Mini-ITX and Micro-ATX combined. I found the top 10 most popular/reviewed mother boards on Newegg were all ATX motherboards.

    When I checked checked the AMD's FM2 socket I found the opposite that there are more Micro-ATX motherboards then ATX and Mini-ITX combined. Interestingly enough of the top 10 motherboards on NewEgg 4 were ATX, 5 were Mini-ATX and only 1 Mini-ITX.

    But really without contacting a prominate motherboard manufacture or a large retailer it would be really hard to speculate how popular the form factor really is.

  • What about for a dev machine? Developers generally want: big CPU, big RAM, and big (or multiple) monitors, but don't really care about super GPUs if they're doing their work in 2D. What's the right option for them? Essentially a gamer setup but with a vidcard spec'd for multiple monitors instead of framerate?

  • @nathan said:

    @PCTRS80: ...Yes, that's what I said in the column.

    If you need multi-GPU setups, a sound card, a RAID card, or tens of terabytes of space--or all of the above--a full ATX board in a full-sized chassis is what you need. But for the rest of us--even most of us--a small-form-factor PC is plenty.

    So it's not "dead" by your own words despite the title.

  • the Micro ATX is smaller version of the ATX. It has excellent performance and ma much lower price. It is especially suitable when you are looking for a motherboard that can suit your personal needs as opposed to business. If you choose to invest in an ATX, only do so when you require all additional PCIe slots.