Best SFX Power Supplies In 2021: For your ultimate ITX and SFF PC Builds

In the past few years, the gaming community has gotten bigger and bigger. Because of this, we’re seeing certain niches in PC gaming explode in popularity. While small form factors PCs still aren’t mainstream, they are gaining popularity. As an enthusiast of ITX builds, it’s a great time to be alive. We have a lot of cases, motherboards, and other components to pick from.

However, it’s not always easy to build inside an ITX case. This is exactly why choosing the right parts is crucial. You’ll want to save space wherever you can. A good way to do this is by getting a small form factor power supply. These are also known as SFX PSUs. However, you can’t exactly buy a “mini” version of a PSU you think it’s good. There’s more to the story here.

High SFX power supplies can get expensive. There are more options these days, but they pale in comparison to the magnitude of ATX supplies available today. But don’t worry, as we’ve done the homework for you. Here are the best SFX power supplies in 2021.

1. EVGA SuperNOVA 550 GM

Most Reliable


  • Fully Modular
  • Very efficient
  • Silent fan
  • 80 Plus Gold certification


  • A bit pricey

238 Reviews

Max Output: 550W | Efficiency Rating: 80 Plus Gold | Modular: Yes | Fan Size: 92mm

EVGA has been the beloved crowd favorite when it comes to reliable power supplies. This has been true for quite a while now. It’s easy to see why, as EVGA never skimps out when it comes to quality. Fortunately, they didn’t hold back while making the SuperNOVA 550 GM. This is the best SFX power supply out there when it comes to pure quality. Let’s go through a brief explanation for why that is.

First off, this SFX power supply is 80+ Gold certified. It has a 90% efficiency at 115VAC and a 92% efficiency at 220-240VAC. This is easily comparable to many high-end ATX PSUs out there. You can sleep peacefully at night knowing you’re not skimping out in that department.

Apart from that, it fits the SFX form factor perfectly. This means that it will fit into many ITX cases with ease. They even include an ATX bracket so you can use it in larger cases. The fan uses a 92mm double ball bearing, and the fan itself is of high quality. What that means is that there is little to no intermittent coil whine.

A single 12V rail provides the best power output and stability. The PSU will save and cover your circuits for the ultimate protection. Did we mention it is fully modular? Apart from the price, this 550W PSU is the best in its class.

2. Corsair SF Series SF750

For Higher-End Builds


  • Lots of power
  • Great for higher-end builds
  • Superb efficiency
  • Whisper quiet operation


  • Stiff and short cables

2,270 Reviews

Max Output: 750W | Efficiency Rating: 80 Plus Platinum | Modular: Yes | Fan Size: 92mm

Next up, we have the SF 750 from Corsair’s SF Series. This PSU is in the second spot for the sole reason that it may be overkill for some builds. Most people building in an ITX case won’t be using all that power. However, if you are someone who can benefit from all that juice, this is a beast of a power supply.

You can probably guess from the name, but yes, this is a 750W power supply unit. It perfectly fits the SFX standard and is a good choice for extreme ITX builds. Furthermore, is 80+ Platinum certified and that means all of your components will be safe and sound in case of a power interruption.

It also gives it impeccable efficiency which means it doesn’t produce much heat either. Apart from that, the fan is whisper quiet despite its small size. The acoustics performance is commendable, even under full load. The rifle bearing does a good job in this regard. It even has a zero RPM fan mode.

Overall this is a great power supply considering the high wattage. If you are someone who is putting together a very premium ITX machine, this PSU is a great option. The only downside is the fact that the cables are very stiff and difficult to manage. It’s also relatively expensive.

3. SeaSonic Focus GX 650



  • Great for small micro ATX cases
  • Large fan keeps the unit cool
  • Fully modular convenience
  • Fanless mode


  • Low quality cables
  • Might be big for extremely small cases

5,041 Reviews

Max Output: 650W | Efficiency Rating: 80 Plus Gold | Modular: Yes | Fan Size: 140mm

Next up, we have the SeaSonic Focus GX-650 power supply. While this power supply unit isn’t exactly the smallest one on this list, it does have its benefits. Let’s get this out of the way first, this is an SFX-L power supply. So, while it will fit into most ITX cases, if you’re going for a specialized case or a super small one, it might not fit.

Despite that, if you can look past it, having a bigger footprint does have its benefits. For example, this PSU is 140mm deep which makes it still smaller than most ATX power supplies. It uses a 135mm fan, which is quite larger than the 92mm fans in smaller SFX cases. This makes the entire unit quieter, and it also pushes a lot more air in terms of volume.

The PSU is also fully modular, so you don’t have to cram any extra cables inside your case. This is especially helpful for cases with poor cable management. It is 80+ Gold certified, so you need not worry about efficiency and all that. Premium fan control is another bonus feature. You can turn on fanless mode for whisper-quiet operation. This can be done on the fly by using the button on the back.

Apart from that, Seasonic even includes a 10-year warranty, which shows their confidence in the product. The only gripe we have is that the included cables aren’t of the best quality.

4. FSP 350W Mini ITX Power Supply

Best For HTPCs


  • Perfect for HTPCs
  • Affordable price
  • Good efficiency


  • Poor fan performance
  • Cables are hard to work with

Max Output: 350W | Efficiency Rating: 80 Plus Bronze | Modular: Yes | Fan Size: 80mm

So far, we’ve been talking about power supplies for gaming PCs. While there are a large majority of people that use SFF cases for gaming, there are those few who utilize them for HTPCs. Home Theatre PCs or HTPCs, don’t usually require a lot of power. They are mostly used to hook up a TV and watch or stream digital content. Rigs like that don’t need a beefy PSU.

For this exact reason, the FSP 350W Mini ITX is a great option. It uses a single 12V rail to power both the CPU and GPU. This FSP power supply will easily fit into any Micro ATX and Mini ITX cases you can think of. It is also 80+ bronze certified. This means that it will provide a minimum of 85% efficiency at a typical load. That’s more than enough for an HTPC.

The included 80mm fan is smaller than others on the market. It isn’t loud, but the noise coming from it can be audible at times. The real problem is that it does not move a whole lot of air, which might be a dealbreaker for some people. Apart from that, this is a great budget power supply. Just don’t expect to use it in a dedicated gaming rig anytime soon.

5. SilverStone Technology 450W PSU

Budget Pick


  • Affordable pricepoint
  • Good efficiency for the money
  • Great for entry-level builds


  • Low quality cables
  • Some struggle with beefy GPUs
  • Loud fan at low RPM

113 Reviews

Max Output: 450W | Efficiency Rating: 80 Plus Bronze | Modular: No | Fan Size: 80mm

Last but definitely not least, we have the SilverStone 450W SFX power supply. SilverStone has been in the game for a long time, so it’s not surprising to see them make this list. This 450W SFX PSU is a great budget pick for lower-end systems. However, it is not without its drawbacks.

First, let’s talk about the good stuff. This power supply has an 80+ Bronze efficiency with a 12V single rail. Not bad for a budget power supply. However, note that the 12V rail at 36A may not be enough for beefy GPUs, especially with the 450 watts.

The PSU is well designed and doesn’t stand out too much. It is noticeably quiet at a higher RPM and the cables are protected by the black sleeving. Sadly, the cables are a bit short and hard to work with. The fan is also annoyingly loud at low RPM. Apart from that, the fan doesn’t move a lot of air, and this can be a dealbreaker if your case is particularly jam-packed.

Still, it’s not a bad option considering the price. Just know what to expect beforehand.

Hassam Nasir
As a Senior Editor, I run, operate, and implement a substantial amount of work at I supervise a team of enthusiastic geeks and also create content strategies. Whenever I am not at my work desk you'll find me tinkering around PC hardware and retro gadgets.