If you have read our previous articles discussing what exactly a PSU is, and what the terms ATX and SFX mean, you should have a pretty good understanding of PSUs and the two major form factor varieties they come in. With that understanding in place, the next step in your journey of building a PC should be decided whether you need an ATX PSU or an SFX PSU.

When is an ATX PSU the right choice?

ATX PSUs can be thought of as the industry standard. The vast majority of available PSUs are ATX, and the majority of PSU builders are likely to need and buy an ATX PSU. If you plan to have a very large ATX case with an ATX motherboard, and you do not plan to move your PC around very often, an ATX PSU is likely the best choice.

For an example of a strong, recently released ATX PSU, you can check out Cooler Master’s own GX III Gold. The GX III Gold 850 is the latest edition in the GX Series and features a broad range of supported wattages, an 80 Plus Gold efficiency certification, a Cybenetics Platinum A- noise level certification, and smart thermal control. The GX III Gold maintains excellent flexibility for use with a myriad of builds, despite its larger ATX form factor. An excellent case to go along with the GX III Gold would be the TD500 Mesh V2, which features a tempered glass front panel, removable top panel, three pre-installed ARGB CF series fans, and space for a 360mm liquid cooler.

When is an SFX PSU the right choice?

If ATX PSUs are the longstanding industry standard, SFX PSUs are the new kids on the block shaking up the PSU scene. SFX PSUs offer a significantly smaller form factor than the ATX standard, and thus a much greater power density. SFX PSUs are great if you want to reduce the overall size and weight of your build, particularly if you want to do an ITX build, which requires a case that is too small for an ATX PSU. SFX PSUs can be used with larger cases as well, as long as you have an ATX bracket and the cables are long enough. This means that you can use an SFX PSU with virtually any build. Cooler Master’s MasterBox NR200P is the perfect example of a mini-ITX case that is an ideal match for an SFX PSU. With features such as triple-slot GPU support and multiple motherboard compatibility options, the NR600P is the perfect small form factor companion to an SFX PSU.

Cooler Master’s V SFX Platinum represents the height of SFX performance. With supported wattages up to 1300W and industry-leading power density, the V SFX Platinum is the most powerful SFX PSU on the market today. If you are looking for the sleek and lightweight form factor of an SFX unit without losing any of the power of an ATX PSU, the V SFX Platinum is a fantastic choice.


In the end, there is no definitively best choice when it comes to choosing between ATX and SFX PSUs. The best choice depends on you and what you want for your build. If you don’t need a lightweight PC, an ATX PSU might be what you’re looking for. If you wish to build a small PC, want a unit with higher power density, but you don’t want to worry about matching the size of your case with the size of your PSU, then perhaps you should go with a PSU such as the V SFX Platinum, which comes with a bracket that allows installation in larger ATX cases.

For a look at a wide selection of both ATX and SFX PSUs, please visit Cooler Master’s PSU page. We also suggest trying out our PSU calculator to assist you in making sure you get the right PSU for your build.

Be the first to knowJoin our mailing list for special offers, new products and contests.