When building a PC you must assemble a variety of components and ensure that they fit and work together. To make this easier, PC manufacturers largely rely on a few standardized guidelines to ensure that various components can all fit together in one case and operate correctly.

For PSUs specifically, there are a few different sizing categories, with the most common being Advanced Technology eXtended, or ATX. You have probably seen “ATX” in a few places while building your PC, perhaps in reference to the PSU, or the case, or even the motherboard. So why are all of these components often referred to as “ATX” and why does it matter?

What does ATX really mean?

ATX is a configuration specification that was originally designed by Intel. It defines specific dimensions for various parts of a motherboard such as where it mounts onto a case and the I/O panel. ATX also defines connector interfaces so that between the motherboard, case, and PSU, everything connects without issue. This ensures that as long as you are using an ATX case, an ATX motherboard, and an ATX PSU, everything will both fit and connect without issue, regardless of manufacturer. For an example of a new ATX PSU, check out Cooler Master’s own GX III Gold. Additionally, Cooler Master’s TD 500 Mesh V2 is an excellent ATX case.

There are several variations of ATX PSUs, but the standard ATX always features a 20-pin or 24-pin connector for the motherboard. Note that while you can use a 24-pin connector with a motherboard that only requires 20 pins, you cannot use a 20-pin connector with a motherboard that needs 24 pins.

How do I know if I need an ATX PSU?

The first thing you should check when determining what kind of PSU to get is what size your motherboard is and what kind of connector it requires. Once you ensure that your PSU is compatible with your motherboard, you can decide how big or small you want your case to be. Due to the relatively large size of ATX PSUs, you will likely need a larger case, such as an ATX case, to ensure that the PSU will fit without issue. Many large cases feature compatibility with a multitude of motherboard sizes, so it is often just a matter of ensuring you do not buy a case that is too small for your motherboard and ATX PSU. Pictured below, you can see Cooler Master’s GX III Gold inside:


At the end of the day, ATX is primarily about sizing. This is important as you want to ensure that your case has enough space to fit everything comfortably and that your cables are able to reach from your PSU to your motherboard and other components.

Cooler Master has a wide range of ATX PSUs. The GX III Gold is a particularly elegant and powerful unit, a new spin on a Cooler Master classic. With a clean and efficient design that improves airflow and dust protection, the GX III Gold also features ATX 3.0 support, fully modular cabling, an 80 Plus Gold efficiency certification, a Cybenetics Platinum A- noise level certification, and a default zero-spin fan with smart thermal control. The GX III Gold is capable of silently and efficiently powering the newest GPUs without breaking a sweat.

For a high-performance ATX PSU like the GX III Gold, you will also need a case to fit it. Our TD 500 Mesh V2 is an ATX case featuring a tempered glass front panel, removable top panel, three pre-installed ARGB CF series fans, and space for a 360mm liquid cooler. With the TD 500 Mesh V2 and the GX III Gold combined, you’ll have an ATX machine capable of meeting and surpassing all your performance needs. For more on the TD 500 Mesh V2, check out the product’s page: https://www.coolermaster.com/catalog/cases/mid-tower/masterbox-td500-mesh-v2/

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