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Smallest Micro ATX Cases In 2021 – Top 7 Rated Reviews

Just like the story of Goldilocks, a micro-ATX (mATX) case is all about finding the right size.

Sometimes your case and motherboard are quite big and filled with extra features that you might never use. But still takes up valuable space on your desk or in your room. And sometimes, your case and motherboard are too small. Making it hard to build and not leaving any room for your components to breathe and cool off for maximum performance.

But, suddenly, you find that magical size in-between and discover that it has everything you need and nothing you don’t. Goldilocks might not have ended up with a micro-ATX case, but she might have appreciated it, given how perfectly it fits in.

Micro is the way to go…

Micro-ATX has become the mid-range between the tiny ITX form factor and the relatively large ATX form factor. But the mATX still comes with a bit of variety, and plenty of builders want to save as much space as possible without having to enter the mini-ITX territory.

So if you’re looking for the best Smallest Micro ATX Cases available, this guide will help you find the one that’s right for you.

Smallest Micro ATX Cases

Top 7 Smallest Micro ATX Cases In 2021 Review

  1. Cooler Master MasterBox Q300P – Most Portable Smallest Micro ATX Case
  2. Corsair Crystal 280X – Best Performance Smallest Micro ATX Case
  3. Thermaltake Core V21 – Best Cooling Smallest Micro ATX Case
  4. Corsair CC-9011048-WW Carbide Air 540 ATX Case – Smallest Micro ATX Case for Gaming
  5. Antec Slim VSK2000 U3 – Smallest Budget Micro ATX Case
  6. Cooler Master Silencio S400 – Smallest Value for Your Money Micro ATX Case
  7. Cooler Master MasterBox Q300L – Smallest Affordable Micro ATX Case

1 Cooler Master MasterBox Q300P – Most Portable Smallest Micro ATX Case

  • Dimensions: 20.08 x 10.90 x 20.74 inches
  • Material: plastic and steel
  • Power supply: 300W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: Yes
  • Expansion Slots: 4
  • Ports: 2 USB 3.0, 1 audio port

The Cooler Master MasterBox Q300P is an affordable mATX case. It’s one of the cheapest on the market, boasting an adjustable input-output panel and the ability to work in at least six different settings and orientations. But what is most impressive is the adjustable handles, allowing you to carry the system with ease.

Another outstanding feature is the modular orientation, which allows you to use the mATX case either vertically or horizontally. And it also offers 28mm of cable management space to keep tangles to a minimum.

More than enough space for components…

Despite being a mid-tower case, it’s compatible with mATX and mini-ATX motherboards, and the components have more than enough space inside. There is a designated length of 360mm for external GPUs, and a 160mm PS2 power supply can also be accommodated. The Q300P also has excellent dust filters with enhancements added to the top, front, and bottom panels.

If thermal performance is a big thing for you, the Masterbox Q300p can fit at least five modules for optimal temperature levels. If you want to add radiators, the case has room for three units. Cooler Master sweetened the pot further by adding three pre-installed fans, which can still achieve decent thermal performance in tandem.

An impressive and efficient mix…

This case also features a useful amount of storage slots, expansion modules, and ports. It has allocated space for two 2.5-inch drives, preferably SSDs, and the case also includes one standalone 3.5″ hard-drive bay.

When it comes to expansion slots for sound cards and other resources, the MasterBox Q300P is equipped with four separate units. You also get two USB 3.0 ports for unhindered data transfers combined with a solitary audio port that supports High-Defenition acoustics.

Our verdict…

The MasterBox Q300P is one of the better looking mATX cases available. It features RGB-inspired fans, transparent side-panel windows, and edge to edge acrylic layering. It weighs 14 pounds, which is still a standard mark considering the four adjustable handles. Overall, this is one of the most flexible and easy-to-use mATX cases.


Cooler Master MasterBox Q300P

Our rating:4.5 out of 5 stars (4.5 / 5)

Pros

  • Three internal storage bays.
  • Transparent side panels.
  • RGB LED-powered fans.
  • Exceptional accessory clearance.
  • Dedicated dust filters at strategic locations.
  • Compatible with the latest RTX 30-series GPUs.

Cons

  • Lacks Type-C port.
  • No external storage bays.

2 Corsair Crystal 280X – Best Performance Smallest Micro ATX Case

  • Dimensions: 15.67 x 10.87 x 13.82 inches
  • Material: Steel, Plastic, and Tempered Glass
  • Power supply: 750W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: Yes
  • Expansion Slots: 4
  • Ports: two USB 2.0 and 2 audio ports

Honestly, the Corsair Crystal 280X is one of the best mATX cases you can buy, flaunting a cube-style chassis made of high-quality materials. The aesthetic layout is completed by the triple-sided glass paneling, highlighting the look of the all-black design.

The interior space is impressive, mainly if you use it with a mini-ITX motherboard, which leaves a fair amount of breathing space for the fans to work at full potential. Another impressive feature is the dual-chamber layout, allowing you to fit GPUs measuring close to 11.8 inches.

Coolers, radiators, or cooling fans for minimal dust build-up?

If cooling is one of your concerns, you can fit in coolers measuring 5.9-inch in terms of height. If you’re more interested in cooling fans keeping dust build-up to a minimum, the case supports six 120mm fans or a liquid cooling option including three 240mm radiators.

The rear chamber is where you can fit wires and cables to achieve a minimalistic layout. Storage options are great, too; you get at least five internal bays to work with. However, the most impressive feature is the dedicated storage compartment.

The Corsair Crystal 280X steals the show…

When it comes to personalization, this case gets it right. For starters, you get access to the Corsair LL120 RGB fans, which look great and display an immersive array of 32 colorful LEDs. Connecting to the fans is the Node Pro digital controller, which allows you to manage the designs and customize the LEDs to your preference.

The side-panel windows allow you to peep into the internal association and admire the light show. The Crystal 280X weighs 15.65 pounds and is one of the few cases that features four expansion slots to connect sound cards, wireless adapters, etc.

The case features dust filters at the top, front, and bottom, which keeps dust build-up to a minimum. Not only that, the mATX case is capable of directing cool air directly to the hottest components. The port arrangement is the weakness of the 280X, giving you two USB 2.0 slots, followed by a single microphone and a single speaker output.

Our verdict…

Overall the Crystal 280X is one of the best mATX cases 0n the market and is compatible with mini-ITX motherboards. There is more than enough room, thanks to the dual-chamber layout, to fit multiple components. The design is stunning, and it has all the right features for a gaming rig.

If you’re a first-time PC builder, this is easily the best mATX case to invest in. This is because the layout ensures zero wire tangles and a clean representation of internal components.


Corsair Crystal 280X

Our rating:4.6 out of 5 stars (4.6 / 5)

Pros

  • Dual-chamber layout.
  • A triple tempered glass panel.
  • Excellent dust filtration.
  • Support for six fans.
  • Five storage bays.

Cons

  • Lacks Type-C port.
  • Thermal performance could have been better.

3 Thermaltake Core V21 – Best Cooling Smallest Micro ATX Case

  • Dimensions: 13.2 x 12.6 x 16.7 inches
  • Material: steel and plastic
  • Power supply: 750W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: Yes
  • Expansion Slots: 5
  • Ports: two USB 3.0 and 1 audio port

Next up, in our Smallest Micro ATX Cases reviews, if you’re a raw performance seeker, the Thermaltake Core V21 is a perfect case to invest in. Even if it was initially hailed as an mATX case, it’s still compatible with mini-ITX motherboards, as well. It’s also one of the best additions to the Core V series, which is best known for the effective thermal solutions.

Keep your cool…

Before moving on to the complex set of attributes, it’s the dual orientation support, linked to the Core V21 that makes an appearance. The overall entity clearance of the Core V21 is also class-leading as it’s capable of including a 200mm front panel fan for achieving excellent thermal performance.

If you have a beefed-up spec sheet already, this mATX case can accommodate 14 fans, which is the limit, depending on the fans’ size. If you want to use radiators instead, there is room for no less than eight. The Core V21 is easily one of the most potent mATX cases for liquid and air-based cooling systems.

Six storage bays and room for upgrade…

The storage support is also fantastic, with six separate bays in total. Furthermore, three of them are dedicated to 2.5″ SSDs and three to 3.5″ HDDs. The case also has a lot of potential if you want to upgrade your components, considering the availability of five expansion slots.

For high-end gamers interested in wattage, the 750W PSU is upgradable to 1500W if you get the right PS2 setup. When it comes to ports and connectors, you can access two USB 3.0 slots and a hybrid audio port with HD output.

Keep an eye on it…

The structure is made of steel and includes plastic accents to keep the case temperatures under control. It also has a transparent window, allowing you to take a closer look at the cable arrangement and fan setup. The case is separated into an upper chamber for better cooling and a lower section, including storage bays and the PSU.

Regardless of the optimized chassis, this might be the best ventilation micro ATX case.

Our verdict…

If you want to set up a beefed-up personal computer focusing on thermal supremacy, the Core V21 is one of the most cost efficient mATX cases you can buy. It weighs 14.3 pounds, which is acceptable considering the chambered layout and multiple fans.

Overall it’s an excellent choice for an mATX case.


Thermaltake Core V21

Our rating:4.6 out of 5 stars (4.6 / 5)

Pros

  • Flexible orientation.
  • Exceptional thermal performance.
  • Chambered layout.
  • Five expansion slots.
  • Durable chassis.

Cons

  • Cable management might be an issue.
  • Overkill for less-powerful PCs.

4 Corsair CC-9011048-WW Carbide Air 540 ATX Case – Smallest Micro ATX Case for Gaming

  • Dimensions: 16.30 x 13.10 x 18.00 inches
  • Material: Carbide
  • Power supply: 750W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: Yes
  • Expansion Slots: 8
  • Ports: two USB 3.0, 1 headphone, and 1 microphone

Corsair’s new case, the Carbide Air 540, is one of the best smallest cases for ATX motherboards, which meets all your requirements and has a brilliant design. The cubic design and dimensions make it seem like an extremely large PC case. But it’s actually a fair bit shorter and shallower than many mid-sized towers despite the width.

Space-saving design…

The case features two internal chambers. Separating the components allowed Corsair to move the PSU and drive bays, reducing the case’s size and depth. The left compartment holds the motherboard and the two 3.5″ hard drive bays, and the other chamber hosts the power supply, two 5.25″ drive bays, and four 2.5″ SSD drive bays.

This results in very little clutter around the key components that generate a significant amount of heat. Therefore, you will need adequate spacing and decent airflow. A pair of 140mm fans are mounted in the front, and there is another 140mm one attached to the rear. They do a good job of keeping things nice and cool.

An absolute joy to build a gaming rig…

As well as being a functional form factor, the Carbide Air 540 is an absolute joy for building a gaming rig. Free access to the surroundings of the motherboard makes it easy to swap components in and out. Giant cutouts on the partition wall between the two chambers allow you to fit CPU cooler backplates, and cables can easily be neatly routed around the back.

The Air 540 is very modular too. If you’re sick and tired of optical disk drives taking up unnecessary space inside your case, you can remove the drive bays. Likewise, the quad-bay 2.5-inch drive caddy on the right is also removable.

Corsair has done an excellent job designing the Air 540. It may seem a little chunky if you’re used to thinner mid-tower cases, but they seem to have thought about everything.

Our verdict…

We haven’t had this much pleasure in building a new machine as with the Carbide Air 540. And it comes down to the hassle-free process because you have a lot of room. The cooling process is outstanding, and you can fit advanced water cooling too. When it comes to the Smallest Micro ATX Cases we tested, this was one of the best.


Corsair CC-9011048-WW Carbide Air 540 ATX Case

Our rating:4.7 out of 5 stars (4.7 / 5)

Pros

  • Includes three high-quality 140mm fans.
  • It has a quieter operation.
  • Support for advanced air and water cooling.
  • Room for two 3.5″ and five 2.5″ drives.

Cons

  • No PSU anti-vibration.
  • It can be a bit noisy.
  • Only two 3.5″ drive accommodation.
  • Its space is limited to two GPUs and two coolers.

5 Antec Slim VSK2000 U3 – Smallest Budget Micro ATX Case

  • Dimensions: 18.6 x 15.9 x 7 inches
  • Material: Plastic and steel
  • Power supply: 300W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: No
  • Expansion Slots: 4
  • Ports: two USB 3.0 and 2 audio ports

The Antec Slim VSK2000 U3 is a good option if you plan to set up a powerful yet affordable PC build. As a slim micro ATX case, it is one of the best for 4K streaming. The excellent thermal performance ensures excellent heat management, regardless of your components producing higher processing TDP levels.

Plenty of room…

The VSK2000 U3 is compatible with micro-ATX and mini-ITX motherboards. And the mini-tower structure also makes room for a TFX-based power supply, which offers the rated power of 300W. The Antec Slim’s slot clearance allows for 200mm graphics cards and CPU coolers as tall as 65mm. Then again, there is already a 92mm fan pre-installed by Antec, featuring extensive temperature control.

The slim case is loaded with storage-centric possibilities as it’s one of the few options available, featuring ODD, HDD, and SSD storage bays.

Simple set up…

Setting up the device is easy as the VSK2000 U3 is best known for a small learning curve.

As for the aesthetics, it’s one of the more modest structures. Courtesy of steel and plastic, the net weight is close to 7.7 pounds making it one of the best lightweight mATX cases in our review.

This mATX case has two USB 3.0 ports or Type-A ports, to be precise, and four expansion slots when it comes to peripheral support. It also carries one audio input and one output slot for a seamless acoustic experience.

Our verdict…

Despite missing out on space for cable management, side-panel windows, and display connections, then this is a leading contender for the best mATX case on the market, especially when it comes to getting the primary job done.


Antec Slim VSK2000 U3

Our rating:4.2 out of 5 stars (4.2 / 5)

Pros

  • Three storage bays.
  • Four expansion slots.
  • Lighter than most mATX cases.
  • Includes a temperature-controlled fan.

Cons

  • No cable management support.
  • No dust filters.

6 Cooler Master Silencio S400 – Smallest Value for Your Money Micro ATX Case

  • Dimensions: 8.27 x 16.46 x 16.06 inches
  • Material: Plastic and steel
  • Power supply: 350W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: No
  • Expansion Slots: 7
  • Ports: two USB 3.0, 1 audio port, and an SD card reader

If you’re looking for a silent mATX, the Cooler Master Silencio S400 is probably your best bet; in fact, it more than likely the Quietest Smallest Micro ATX Case you can buy. Even though it stands tall like a mid-tower ATX, it’s still compatible with micro and mini-ITX boards.

Well ventilated…

Including the standard set of attributes, you also get access to ventilate top panels and innovative sound dampening cushions, which promote an almost whisper quiet usage. The case is still quite sleek despite the additional features. While it doesn’t have a side-panel window, it’s the reversible front cover that stands out.

When it comes to fan support, the small and sleek micro-ATX case can incorporate six 140mm fans. But it comes with two pre-installed Silencio 120mm fans. If you want to take advantage of the radiator support, you can install four radiators in the front, two in the top, and one in the rear.

Storage and cooling…

Storage-wise, it has four slots for HDD and SSD expansions and a single slot for an ODD storage unit. However, the HDD bay is probably the most flexible aspect of the Silencio S400, as it can be shifted back to fit a radiator or moved to the front to hold a PSU. What also stands out is the rubber padding, allowing for a noise-free experience. If it wasn’t for the LED indicators, it’s hard to know if the computer is turned on.

Even though the front and top ventilation add to the credibility of the Silencio S400, it’s the futuristic design that validates your purchase decision, as well as the seven expansion slots. Additionally, there is a slot in the front for an SD card if you further expand the storage support.

Our verdict…

While this is a tremendous micro-ATX case to invest in, you can also go for a more adventurous model featuring tempered glass and side-window paneling. The case is spacious with room for extended cooling.


Cooler Master Silencio S400

Our rating:4.6 out of 5 stars (4.6 / 5)

Pros

  • Silent operation.
  • Sturdy build quality.
  • The front panel is reversible.
  • Comes with a dedicated ODD slot.
  • Two built-in Silencio fans.

Cons

  • Thermal performance could have been better.
  • Doesn’t include Type-C ports.

7 Cooler Master MasterBox Q300L – Smallest Affordable Micro ATX Case

  • Dimensions: 15 x 9.05 x 15.23 inches
  • Material: Plastic and steel
  • Power supply: 750W
  • Compatibility: Micro-ATX and Mini-ITX
  • Side-Panel Windows: Yes
  • Expansion Slots: 4
  • Ports: two USB 3.0 and 1 audio port

The Cooler Master Masterbox Q300L is, like many of our other mATX cases in this review, an affordable yet capable option. The Q300L is compatible with mATX and mini-ITX MOBOs and offers a minimum of 28mm of routing space for excellent cable management.

However, the most stand-out feature on the case is the multiple I/O orientation system, allowing you to fit in components, regardless of your preferences.

Built to last…

The structure is durable, bolstered by steel and plastic. Adding to the design’s appeal, you have acrylic paneling and a transparent side-panel window, which allows an excellent viewing experience. The small form factor entails a PS2 PSU if you’re ok with bottom-mounted support.

The cooling support lets you install six fans in addition to three radiators, which achieves a substantial liquid-based thermal performance. The dust filters found on three sides adds even more to the cooling performance. The magnetic filters ensure that the Q300L remains clean for extended periods.

Any way you like it…

The modular mATX case supports up to six different orientations and allows you to position the case either in horizontal or vertical positions. Other efficient and reliable features include three storage bays, two for 2.5″ drives and one internal bay for 3.5″ drives. It also comes equipped with four expansion slots, suited for wireless cards, sound cards, and other components.

The mATX has two USB 3.0 ports for necessary data transfers. The Audio port is a separate hybrid HD port.

Our verdict…

The MasterBox Q300L from Cooler Master is one of the most sought after mATX cases. The budget-friendly price has a lot to do with that. If you don’t want to spend a fortune on a case and buy relevant internal components, the Q300L is an excellent option.


Cooler Master MasterBox Q300L

Our rating:4.5 out of 5 stars (4.5 / 5)

Pros

  • Includes perforated magnetic filters.
  • Six different I/O orientations.
  • Affordable.
  • Transparent side-panel.
  • Accessible cable management.

Cons

  • Not enough storage bays.
  • The filter screen isn’t sturdy enough.

Smallest Micro ATX Cases Buyers Guide

We understand that choosing the best-suited mATX case can be challenging, especially with the market overflowing with options, one promising to be better than the other. With all the available features and specs, it’s not easy to decide which case has the best performance and suits you the most.

Likewise, it’s difficult to find answers to all your questions by only looking at a list of products. So before you buy a case from our list, let’s talk about the features you should consider when finding the best smallest mATX case that works for you.

Design and customization…

Cooler Master MasterBox Q300P Micro-ATX with Dual 120mm ARGB Fans, Front/Top Dark Mirror Panel, Transparent Acrylic Side Panel, Adjustable I/O

One of the first things you will notice is the design. Most micro-ATX cases come with aesthetics that makes you want to buy one straight away. Who doesn’t want a case with a tempered glass side-panel that looks edgy and cool? But having a transparent side-panel means you have to put in extra work hiding away cables and ugly parts. If you’re lazy, you shouldn’t buy a case with tempered glass.

The RGB lighting is another enticing feature, especially if you’re a gamer. You can customize the LEDs to match your likes, and it looks incredible in the dark.

The market is also overcrowded with cases that offer endless customization. Whether it’s changing the position of the I/O panel or the orientation of the case, you can be sure to find a case that fits you.

Cooling options…

If you plan to use liquid coolers, you must choose a case with adequate openings, making it easy to install and clean the systems. Also, keep in mind that not all cases can accommodate liquid cooling.

If you already own a cooling system, you need to make sure that the case you want can fit the cooler. Usually, cases have specs that indicate the radiator size it can support. Choosing a case with vents on the sides also reduces the risk of overheating.

Noise…

Optimal airflow is critical for running powerful components and can only be achieved by installing fans. However, the more fans you have, the noisier the case can get.

Whatever you do, don’t sacrifice airflow for noise reduction since overheating components can cause thermal throttling of the hardware. Instead, opt for a case with noise filters and liners to reduce the noise levels.

Dust Filter…

If you work in a dusty environment, it’s essential to choose a case that prevents dust from entering the system. Cases tend to gather dust quickly, and the build-up of dust affects the PC’s performance.

So, make sure the case has adequate dust filters that can also be easily accessed. They should be removable so they are easy to clean and don’t get clogged up. Some cases also have magnetic dust panels, which further prevents build-up inside the case.

Space for Components…

You want a case with enough space to handle all the pieces of equipment you want to install. A good tip is to make a list of all the components and cross-check the list with your desired case specs.

The number of drives, expansion slots, radiators, coolers, and even the motherboard you want, means the type of case you need may vary immensely. When choosing a case, make sure that it supports the components you want to use.

Having enough space for the components is one thing; you also need to make sure that the case has enough space around the components for easy installation.

Durability…

The material is one of the most critical factors. The durability determines how long the case will last, and a good case has the right combination of sturdy and fragile parts. Some components may require the material to support their weight without crumbling, while others need a soft landing pad to prevent accidental damage. That said, cases made out of steel and plastic are usually the best choices.

Budget…

Probably the most crucial aspect of them all. Don’t get mesmerized into buying a case with unnecessary features that blow your budget. Simply choose the case that works best for you within your limits.

It’s also important not to cut back on the quality, just to save money. Durability and how compatible it is with other components is essential. Otherwise, you might spend more money replacing a low-quality or a bad case.

Looking For Something Else?

Corsair CC-9011048-WW Carbide Series Air 540 Windowed ATX High Airflow Cube Performance Computer Case with White LED Fan - Arctic White

It’s never been easier to build your perfect computer system. So, check out our in-depth Best Budget PC Cases Review, our Best Budget Gaming Chairs under $200 Reviews, our Best Gaming Desk Review, our Best Ergonomic Keyboards Reviews, and our Best Ergonomic Mouse Reviews to find out what you should buy in 2021.

Also, don’t forget to take a look at our comprehensive Samsung C32HG70 Review, our ASUS VG279Q Review, our Best Standing Desks Reviews, and our in-depth reviews of the Best Computer Speakers currently on the market.

What Are The Smallest Micro ATX Cases?

Each of our featured mATX cases caters to a specific breed of computing. However, don’t forget that micro-ATX cases are budget versions for gaming considerations and usually only have one GPU-configuration. If you’re looking to build a premium gaming rig, you should opt for a standard ATX or the NZXT H510 mATX that we didn’t review this time.

All micro-ATX cases on our list have something for everyone’s preferred preferences. This includes power, thermal performance, silent operations, portability, premium gaming support, and budget.

Lots of options for your personal needs…

If it’s the performance you are after, we recommend the Corsair Crystal 280X or the Cooler Master Masterbox Q300p. For silent operations, you should go with the Cooler Master Silencio S400. The only case that qualifies for portability is the Cooler Master Masterbox Q300p due to the adjustable handles. Lastly, if you’re on a very strict budget, not many cases beat the Antec Slim VSK2000 U3.

But our top choice for the Smallest Micro ATX Cases is the…

Cooler Master Silencio S400

This is because it has almost every attribute mentioned. With seven expansion slots, support for liquid cooling, silent operation, and even the elusive ODD storage bay, we can safely say, “case closed!”

Until next time, enjoy your computer builds.

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