5 Best ‘Smallest’ ATX Cases for Compact PC Builds

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The trend of building smaller and smaller PCs is growing in 2020, with case manufacturers, new and old, investing heavily in bringing more small form factor cases (SFF) to market – under 20L in volume. These SFF cases, are impressive and compact in size, and fit ITX form factor motherboards, but do not support the regular form factor ATX. If you’re looking to do a (relative) compact PC build but don’t want to opt for a Micro-ATX or Mini ITX motherboard, and rather stick with the ATX format, then in this guide we will show you the best and smallest ATX cases on the market in 2020.

Included in this article is a comparison chart of popular ATX cases, with their case volume amongst other specifications listed for comparison. In addition, we will show you our favorite small ATX cases to consider – and what we would personally pick if we were to do a small ATX build.

Our Recommendations

Fractal-Design-Meshify-CFractal Design Meshify C36.8Lprice check
Riotoro-CR1080-Small-ATX-CaseRiotoro CR108032.7Lprice check
Raijintek-Thetis-Compact-ATX-PC-CaseRaijintek Thetis 27.7Lprice check
Thermaltake-Core-G3-ATX-Case-SmallThermaltake Core G323.6Lprice check
Sliger-Cerberus-X-Smallest-ATX-Case-2019Kimera Industries Cerberus X19.4Lprice check

Fractal Design Meshify C (36.8 L)


Our first pick of the list comes from Fractal Design with the Meshify C, their compact ATX offering that has just over 36 litres of internal capacity. It’s one of our favorite ATX cases on the market, and it really is a jack of all trades case, with a beautifully understated design, as well as being super quiet thanks to its sound dampening, and the tempered glass side panel really is just something else.

From a functional standpoint, the Meshify C offers awesome airflow and thermals, with reported 7 degrees lower temperatures when compared to the NZXT Elite (Gamers Nexus) and even the Define C, this case will not only look great but also help keep your system cool and negate heat away from the components effectively.

Cable management is made easy, and theres plenty of clearance for chunky components, with up to 172mm coolers and 315mm video cards being supported.

Okay, it’s not exactly the cheapest or smallest ATX case on the market, but when we say you really can’t go wrong with this case, you have to believe us on that. You will not regret going for the Meshify C.

Riotoro CR1080 (32.7 L)


The second small ATX case in our list that will accept a full-size ATX motherboard is the Riotoro CR1080, coming in at just under 33 litres internal capacity. It features a sleek, black minimalistic design with a bulged side window – allowing you to show off your build from the outside. It’s not just small components that can fit in the CR1080 despite its compact size, too. The CR1080 fits the standard ATX form factor and graphics cards of up to 300mm in length in a dual chamber setup – where the PSU and other component sections are located in opposing areas of the case – similar to the Dan Cases A4 SFX.

Where effective cooling can be an issue in compact mini-tower builds where airflow is restricted, the CR1080 allows for two 120mm radiators on the front panel, and thus the ability to install an AIO cooler system in the case. When compared to the Carbide Air 740, however, temperature levels of the CR1080 were considerably higher (10-15 degrees) and noise only a few decibels louder than the Air 740 – showing that the CR1080 has an impressive temperature-to-noise ratio.

There are some issues with the CR1080 case, however – such as pretty poor cable management making this PC case certainly not easy to build with, and this would frustrate many PC builders wanting a build with clean and organised cable management.

At only $80, this is certainly one of the cheapest small ATX cases on the market – so if you’re looking to do a budget yet compact ATX build then the Riotoro CR1080 will be a good case to consider.

Raijintek Thetis (27.7 L)


One case that gets recommended time and time again for compact ATX builds on Reddit and forums is the Raijintek Thetis. At just 27.7L volume, don’t be fooled at what this PC case can fit. With space for full ATX PSUs, graphics cards of up to 280mm in length, four hard drives and even a 240mm radiator – you will be hard pressed to find a component that this compact ATX chassis can’t fit!

Available in either black or silver, this clean minimalistic designed case is made of highly durable aluminium and features a great-looking glass side panel – which does a great job of making any PC build look great. It’s important to note that this is an inverted case – meaning that the graphics card will actually be facing upwards, and thus when planning the airflow and cooling setup of the Thetis you will want the exhaust of air at the top of the case, pulling hot air away from the graphics card, and a 120mm fan as the lower intake.

It’s not the easiest PC case to assemble in, but this is the case (no pun intended) for most compact ATX PC cases since space is so limited. Another nitpick is that the Thetis only includes one 120mm fan (which isn’t the quietest) despite its premium price tag.

All-in-all, the Raijintek Thetis is one of the most popular options for building a compact ATX PC in 2020, and with good reason. Highly recommended from TechPowerUp, you will certainly not be disappointed with the Raijintek Thetis. You have our word.

Thermaltake Core G3 (23.6 L)


Our second to last PC case on our list that we recommend for small ATX builds is the Thermaltake Core G3, a very slim compact case that almost is small enough to be defined as a small form factor case (under 20L volume) at only 23.6L capacity.

Built from durable steel (unfortunately not aluminum) the Core G3 doesn’t have the same ‘premium’ feel compared to the aluminum construction of the Fractal Design Meshify C or Cerberus X, but it’s still good and certainly doesn’t feel cheap – despite its low price. The Core G3 has great dust filtration and features a large acrylic glass side window which we think looks fantastic.

Unlike the other cases we have mentioned in this article, the Core G3 does not fit full-size ATX power supplies, only the smaller SFX form factor and CPU coolers of up to 110mm in height. Unfortunately, that rules out popular air coolers such as the Noctua NH-D15 or Dark Rock Pro 4 – but water cooling is supported with up to 240mm radiators able to be installed internally – so a compact AIO cooled ATX build is possible with the Core G3.

The Core G3 is one the smallest PC cases you can buy that can support the ATX form factor (without resorting to Micro ATX or Mini ATX) and makes a great contender for HTPC builds in 2020. It’s not the best in terms of airflow and cooling, hence we recommend this build only for water cooled/AIO setups. Cable management is pretty non-existent, too – so keep that in mind if you care about a clean and tidy setup.

Despite these drawbacks, the Thermaltake Core G3 should certainly be worth considering for your next compact ATX build given its super compact size, great looks and low price.

Cerberus X (19.4 L)


One of the most exciting PC cases to be released in the past few years has to be this case, the Sliger (Kimera Industries) Cerberus X. Claimed to be the ‘worlds smallest ATX case’ at under 20 litres in capacity, if you’re looking for the absolute smallest ATX build then you can’t get smaller than this. This SFF case not only supports up to extended ATX motherboards, but it also supports ATX power supplies, up to two 280mm radiators for water cooled builds and air coolers of up to 148mm in height. This compact ATX case really does it all, and build in sleek black aluminum, we think it is the best looking small ATX case, too. What we think is most impressive of all is that the Cerberus X has eight PCIe expansion slots able to support up to four graphics cards of up to 330mm in length, allowing for quad SLI setups in a small form factor case. Bonkers.

There’s nothing quite like the Cerberus X, and you’ll probably never find another case quite like it – at least for the next few years. I can go on and on about this case, but I don’t want to bore you. If you’re looking to build in this case, it will set you back $250, but despite this high price, you won’t be disappointed. You get what you pay for, every user we have spoken to who has built with this case has never been happier about sacrificing their wallet for the Cerberus X. Go with your gut and get this PC case if you’re looking for the absolute best compact ATX build.


Fractal-Design-Meshify-CFractal Design Meshify C36.8Lprice check
Riotoro-CR1080-Small-ATX-CaseRiotoro CR108032.7Lprice check
Raijintek-Thetis-Compact-ATX-PC-CaseRaijintek Thetis 27.7Lprice check
Thermaltake-Core-G3-ATX-Case-SmallThermaltake Core G323.6Lprice check
Sliger-Cerberus-X-Smallest-ATX-Case-2019Kimera Industries Cerberus X19.4Lprice check
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