If you’re looking for a power supply that provides you with a bit more space in your PC build, then purchasing an SFX PSU might just be the option for you. The SFX format is just a smaller version of the ATX standard. For all intents and purposes, it functions in the same way and comes with all of the same connectors. Building in a custom case will likely require you to shop for an SFX power supply since smaller cases oftentimes don’t fit a full ATX power supply.
Choosing the right PSU for your setup depends on a number of factors, including price, size, wattage, rating, and design. This is why, in this guide, we’ll walk you through a number of PSU choices that highlight the best budget, high-end, and efficient
options on the market right now.
Products at a glance
- Best SFX PSU
Corsair SF850L
- Wattage: 850W
- Form Factor: SFX-L
- Rating: 80 Plus Gold, Cybenetics Platinum
- Design: Fully modular
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Best budget SFX PSUSeasonic Focus SGX-750
- Wattage: 750
- Form Factor : SFX
- Rating : 80 Plus Gold
- Design: Fully modular
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Best high-end SFX PSUSilverStone Technology SX1000R
- Wattage: 1000
- Form Factor: SFX
- Rating : 80 Plus Platinum
- Design: Fully modular
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Best SFX PSU for efficiencySilverStone Technology 800W SFX-L
- Wattage: 800W
- Fom Factor: SFX-L
- Rating : 80 Plus Titanium
- Design: Fully modular
How we picked the best SFX PSUs
Before going into our picks, it’s important that you know some basics when it comes to picking your future power supply. Ratings and 80+ certification can be a little bit confusing for the PC building newbie, so we’ve attached a graph that can help clarify these seemingly random values, giving you a better idea of how PSUs work.
A power supply is basically an AC adaptor. It converts alternating current to direct current. For reasons of efficiency and safety, you should go for 80+ certified. This guarantees that at the 20, 50, and 100% loads, your power supply will deliver at least 80% efficiency when converting. The remaining 20% will dissipate as heat. The Bronze, Silver, Gold, Platinum, and Titanium ratings help further distinguish power supplies based on efficiency. More efficiency means lesser power draw and cooler temperatures.
Picking the right PSU for your system is really, really easy. Pick one that’s rated to deliver around 20% more wattage than your parts consume, make sure it’s from a reputable manufacturer, and pick as high of a rating as your pocket allows you to. The ratings don’t affect build quality whatsoever, so picking any 80+ rated PSU from a reputable manufacturer is sure to deliver good build quality and solid power delivery
Our top picks
- Wattage: 850W
- Form Factor: SFX-L
- Rating: 80 Plus Gold, Cybenetics Platinum
- Design: Fully modular
- Fully modular
- Low price
- PCIe 5.0 compatible
If you’re looking for something that doesn’t compromise on power or efficiency for a reasonable price then the Corsair SF850L could just be the option for you. This handy power supply takes our top spot because, despite its size, it packs a powerful punch when paired with the right components, and with an 80 Plus Gold rating, the SF850L does not disappoint when it comes to running cool and silent.
Rated for 850 watts, the Corsair SF850L is a great choice for a small form-factor powerhouse. Its fully modular design helps to save even more space within your setup. On top of this, the SF850L is ATX 3.0 PCIe 5.0 compatible, future-proofing your build so that you don’t have to think about buying a new PSU any time soon. The sleeved cables come detached, allowing you to achieve optimal cable management much more easily. Make sure you store the extras in a safe place since you might need them for future upgrades.
Measuring just 125 x 63.5 x 130mm, the SF850L is perfect for small form factor PCs with its SFX-L design. If you only have a larger case, then the SF850L comes with a with an adapter that will allow you to use it in a larger size. Although, it is recommended that this PSU is used in a case more fitted to its size, check out our best PC cases under $100 guide to see what options are out there.
As the PSU is just a shrunken-down option it still is mostly the same as the standard ATX options
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What users say
Like us, many customers are impressed with the features and overall power of the Corsair SF850L. So much so, that users have taken to Amazon to share their reviews on the product. Mainly customers express their satisfaction with the noise level, performance, and size of the product.
One user states, “Great product no problems and well made. Easy to install and use. The shipping was fast and pricing was fair”, this demonstrates the multitude of reasons why the SF850L could be the right SFX PSU for you. Another user writes,”Despite its small size, it packs a powerful punch, ensuring stable and efficient power delivery to your components”, this shows just how powerful the SF850L is.
- Wattage: 750
- Form Factor : SFX
- Rating : 80 Plus Gold
- Design: Fully modular
- Fully modular
- Low price
- Hybrid fan control
The Seasonic Focus SGX-650 is an SFX-L power supply, with a variety of technologies that allow it to be one of the best choices for your future compact build. This compact PSU is a great option for those looking to save money while building their PC. This fully modular SFX PSU comes in at a price of just under $100, making it the perfect combination of power and price.
Measuring just 125 x 100 x 63.5mm, the Seasonic Focus SGX-650 is a great choice for those hoping to save on space when building their PC. On top of this, it implements a fully modular design, which means additional space is added if you don’t want cables cluttering your setup. This SFX offers 750W at a 80 Plus Gold rating, making it compatible with some of the best and powerful PC components on the market at the minute.
If you’re hoping for a PSU that doesn’t distract with a loud fan, then Focus SGX-650 could be the right choice for you. This impressive PSU offers premium hybrid fan control, which functions at three operational stages, fanless mode, silent mode, and cooling mode.
What users say
Customers have taken to Amazon to share their thoughts on the Seasonic Focus SGX-650. Unfortunately, isn’t well reviewed with Amazon showing only 35 users thoughts on the product. This lack of customer reviews should be something you consider if you’re thinking of purchasing this product.
The majority of the reviews seem to be positive, with customers demonstrating a satisfaction with the SGX-650’s affordability and reliability. One user states, “Nice and reliable product. Very silent”, showing how the PSU’s hybrid fan control helps to creat an quiet work environment.
- Wattage: 1000
- Form Factor: SFX
- Rating : 80 Plus Platinum
- Design: Fully modular
- Fully modular
- Higher wattage
- Higher price
For our high-end SFX PSU option we’ve chosen a product with a wattage capable of handling the most powerful PC components out there at the minute. The SilverStone Technology SX1000R offers the best in power and efficiency, however, this is reflected in its more premium price. The SX1000R comes in at a price of $270 on Amazon, although this number may vary, making it the most expensive PSU on this list.
This fully modular 80 Plus Platinum SFX offers an impressive 1000W, which helps to create a reliable base capable of powering components under heavy tasks. On top of this, this SFX PSU demonstrates high efficiency with Cybenetics Platinum certification, and a high quality construction with all Japanese capacitors. The fully modular design of this SFX PSU means that you can save even more space within your build, due to it’s detachable cables.
The SilverStone Technology SX1000R supports 12VHPWR PCIe connector with SFX12V 4.0 and PCIe Gen 5 standard, making it a future proof option that you won’t have to think about replacing for a long time. One factor that should be considered when using this PSU is that it should only really be used with components that require this amount of power, if it is used on anything lower then the additional wattage will be considered waste.
What users say
Customers have taken to Amazon to share their thoughts on the SilverStone Technology SX1000R, mentioning that they like features including its temperature, modularity, and the quality of the product. One customer states, “So far this power supply has been super solid. No issues after a couple of power outages, and seems to put out consistent power. Easily powers high end hardware with no unexpected shut downs”, demonstrating user satisfaction with the consistent power of the PSU.
- Wattage: 800W
- Fom Factor: SFX-L
- Rating : 80 Plus Titanium
- Design: Fully modular
- Fully modular
- Very efficient
- Quiet operation
- Higher price
- Short cables
For our last SFX choice, we’ve picked a PSU with a high efficiency rating, perfect for those who plan to use their power supply with demanding components. The SilverStone Technology 800W offers the best in efficiency with a 80 Plus Titanium rating, guaranteeing efficiencies between 90% and 96% with 10-100% loading. This makes it the perfect SFX option for customers who rely on their system for heavy workloads and demanding gaming.
The efficiency and higher wattage of this PSU are reflected in its price, with it being sold for $203 on Amazon. Although not quite as expensive as the SilverStone Technology SX1000R, this PSU still comes in on the higher end of the price ranges within this guide. Measuring just 126 x 130 x 63mm this PSU offers a great option for those focusing on creating a more compact build, and with its fully modular design, you’ll be able to save even more space by detaching unused cables.
With this PSU you can expect quiet operation, due to its silent running 120mm fan with an advanced semi-fanless function. This PSU comes equipped with a high-quality construction due to its Japanese capacitors, meaning you’re getting a reliable product with a price to match.
What users say
When considering which PSU is best suited to your setup, it’s important to look at reviews online to see if user experiences match your expectations of the product. The SilverStone Technology 800W has received a number of positive reviews on Amazon, with users expressing their satisfaction with the performance, noise level, and the quality of this product.
One customer states, “Runs quietly – I’ve never heard this thing over the ambient sound my PC makes”, demonstrating the quality of noise control this PSU has. Another customer states, “It comes with the standard modular cables, but shortened for the sff user. I ended up having mine custom made for my case”, showing that you may need to invest in extra cables to get your desired setup.
Features and considerations
When deciding on what SFX PSU is right for you it’s important to consider a number of factors. One of the main things to look at is longevity. How long do you think this PSU will last? And, will it work well with my system settings for an extended period of time? Usually, PSUs will have a warranty that demonstrates how long manufacturers believe their product will remain a reliable source of power. It’s a good idea to look at this warranty and decide whether you think this means the product will last you a long time.
Another way to decide this is by looking at the future-proofing technology that has been included in the product. For example, if a PSU includes PCIe 5.0 then it will be able to withstand modern technologies that have been made with this feature. On top of this, efficiency is an important feature to consider when purchasing your PSU. Looking at the ratings of PSUs is a great indicator of how efficient your PSU will be. Anything with an 80 Plus rating will provide you with a reliable and efficient source of power.
What is the difference between SFX and SFX-L PSUs?
Both SFX and SFX-L PSUs are designed to save space within your build, however, there is a slight difference between the two in terms of dimensions. SFX-L are 30mm longer than SFX PSUs, so if you’re looking for the most amount of extra space in your system then opting fo a smaller SFX-L might be the right choice for you.
