Best SFX PSU: Our Top SFX Power Supply Recommendations

Check out our SFX PSU review, and find the SFX PSU best suited to your next PC build!

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If you are looking to build a small form factor (also known as SFX, SFF or ITX) PC, then it is essential to invest in the very best SFX PSU. These tiny units are capable of providing ample power supply to compact computers, specially designed to fit small-volume cases whilst maintaining all the important quality-of-life features of a full-size PSU.

We’ve scoured the market for the best SFX power supply units on offer, factoring in both budgetary and wattage requirements to ensure that you find a suitable no matter your build specifications. That said, there is a limit to the wattage available in even the best SFX PSUs – make sure that you get the right power supply for your build by using a PSU calculator.

Best SFX PSU: Corsair SF750

Corsair SF750

Output Wattage

750

Compatible Devices

Personal Computer

Cooling Method

Air

Pros
  • Highly efficient
  • Easy installation
Cons
  • Premium pricing

It would be impossible to put together an SFX PSU review without mentioning any Corsair products. The SF750 is a fantastic 750W PSU for small form factor PC builds, with all the quality features you’d expect from a top-tier power supply unit. With an 80+ Platinum efficiency rating, the SF750 lets no energy go to waste, saving power as well as space. And with a fully modular design, you’ll have no trouble installing it snugly into your mini case. Though you are paying a premium for the quality of this SFX PSU, it is well worth the price in our eyes, and we’re happy to name it our best SFX power supply!

Best Quiet-Running SFX PSU: Seasonic Focus SGX650

Seasonic FOCUS SGX650

Wattage

650W

Certification

80+ Gold

Modular?

Fully Modular

Pros
  • Middle-ground wattage
  • Silent running
  • Efficient
Cons
  • Higher-than-average cost

As our name suggests, we like a quiet-running PC here at Silent PC Review. For an ITX PSU that is as small as it is silent, look no further than the Seasonic FOCUS SGX650. In using the standard 650W model, you’ll have a reasonable amount of wattage with which to power your PSU. Once you get through an easy installation with a fully modular design, you’ll be treated to the incredible silent running that we love Seasonic PSUs for. Though it is more expensive than the average power supply, you’ll practically forget this PSU is installed with its quiet operation. We’re happy to call it one of the best SFX power supplies on the market!

Best 600W SFX PSU: Corsair SF600

Corsair SF600

Wattage

600W

Efficiency

Platinum

Modularity

Fully-modular

Pros
  • Platinum efficiency
  • Fully Modular
  • Decent wattage
Cons
  • High price point

Another top-tier Corsair PSU, the SF600 rules the middle bracket of SFX PSU wattages. At 600W of power, you’ll have plenty of power for your ITX PC build – and with 80+ Platinum efficiency, none of it will go to waste. There are plenty of configuration options with a fully modular design in a small form factor, and the SF600 performs consistently well even at 230V of power. And whilst the price does sit a little above average, we recommend the investment in one of the best SFF PSUs on the market!

Best Budget SFX PSU: SilverStone ST45SF

SilverStone ST45SF

Output Wattage

450

Compatible Devices

Personal Computer

Cooling Method

Air

Pros
  • Affordable
  • Compact footprint
Cons
  • Low efficiency
  • Non-modular 

For a barebones SFX PSU on a shoestring budget, the SilverStone ST45SF is an optimum solution. As the best budget SFX PSU, it manages to strike a balance between price and quality nicely with a price that hovers under $100. With 450W of power on display, the ST45SF packs a lot into a truly tiny package: as one of the smallest PSUs on this list, the form factor is truly pushed to the limit with this micro power supply unit. There are some drawbacks, however: at 80+ Bronze efficiency, the money you save on the PSU will be lost over time on energy costs. Additionally, the non-modular design can make for a less-than-surgical installation process, and no opportunity for custom cables. But for unrivalled upfront value and form factor, the ST45SF is the best budget SFX PSU on the market!

Best SFX-L PSU: Corsair SF850L

Corsair SF850L

Corsair SF850L

Wattage

850W

Certification

80+ Gold

Modular?

Fully Modular

Pros
  • Excellent wattage
  • Efficient
Cons
  • Poor cable length

A massive leap in PSU power, the Corsair SF850L is the best SFX-L PSU as well as the best 850W SFX PSU for those needing some extra power for their mini PC. With 80+ Gold efficiency and a fully modular design, this PSU combines all our favorite PSU features, along with top-notch wattage for both future-proofing and smooth running. If we were to pick something to dislike about this otherwise stellar PSU, it would be that the Corsair cables are short, even by SFF PSU standards – which can be difficult to remedy without investing in cable mods. If you can look past this nitpick, however, you’ll see that Corsair’s reputation for top-notch power supply continues, with another of the best SFX power supplies being part of their range!

SFX vs ATX Power Supplies: What’s the Difference?

ATX stands for “Advanced Technology Extended”, and has been the standard for most PSU configurations for custom PCs. It is the most effective means of powering a computer and the one most readily catered to by the PSU market, with new ATX 3.0 technology allowing for faster and higher quantities of power delivery.

SFX, confusingly, stands for “Small Form Factor”. Equally confusing, it can also be abbreviated to ITX – in fact, the least likely acronym you’ll see is “SFF”. These are all the catch-all terms for smaller models of ATX PSUs, using broadly the same design but condensed into a much smaller model. Mini PC builds have become more commonplace, and PC enthusiasts like to invest in the best SFX PSUs for the best performance in their small form factor build.

Aside from their smaller size, there are few differences between ATX and SFX in the design sense, though SFX PSUs are inherently limited by their size. SFX PSUs generally have lower wattages even at the higher end of the spectrum compared to their bigger siblings: ATX PSUs can have as much as 1600W of power in them, whereas even some of the best SFF PSUs have no more than 850W.

FAQs

What’s the difference between an SFX and SFX-L PSU?

SFX-L PSUs are longer than the average SFX PSU, though both are equally compact and condense the best power supply into your ITX PC build!

Are SFX PSUs worth it?

If you want to build a mini PC, then investing in the best SFX power supply units is an absolute must, with efficiencies and wattages that rival full-size ATX models at competitive prices!

In Summary

That concludes our picks for the best SFX power supplies on the market today! If you want condensed PC performance with plenty of power, then our top picks are sure to be perfect for your next build!

At the other end of the spectrum, the market for full-size ATX PSUs has never been bigger, both in wattage and product range – check out our guide on the best 1200W PSUs to make sure your next-generation PC gets all the power it needs!

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