There is a particular kind of PC build where every millimetre is contested. The graphics card is 3 slots, the cooler overhangs the side panel, and the power supply has to disappear into a corner that a standard ATX unit simply cannot reach. For those machines, the best SFX power supply is not a nice-to-have; it is the only thing that makes the build physically possible.
We spent the last several weeks working through every SFX and SFX-L unit that clears a real quality bar, reading the spec sheets, the warranty terms and the owner feedback line by line. What follows is the result: ten power supplies that we would actually build a small form factor PC around in 2026, ranked by the things that matter once the case is a shoebox.
Two questions come up before anything else. First, how much power do you actually need, because SFX hardware has historically been capped around 750W and buyers routinely oversize. Second, what does ATX 3.1 change, which is the term that appears most often in current buying advice. We answer both properly, with numbers, further down. If you want the short version, the bench power supply picks we keep coming back to follow the same efficiency-first logic we apply here.
Table of Contents
Top 3 Picks for Small Builds in September 2026
Cooler Master V750 SFX Gold
- 750W true SFX footprint
- ATX 3.1 with 450W 12V-2x6
- 80 PLUS Gold and Noise A
- 10-year warranty
Corsair SF750 (2024)
- 80 PLUS Platinum
- Zero RPM fan stop
- 105C Japanese capacitors
- Bracket included
Lian Li SP750 V2
- 750W with native 12V-2x6
- ATX 3.1 certified
- Built to 63.5mm SFX spec
- 10-year warranty
The 10 Best SFX Power Supplies in September 2026
| Product | Specifications | Action |
|---|---|---|
| Cooler Master V750 SFX Gold |
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| Corsair SF750 (2024) |
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| Lian Li SP750 V2 |
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 ASUS ROG Loki SFX-L 750W |
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 SilverStone SX700-PT |
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 SilverStone SX700-LPT-USA |
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 SilverStone SX700-G |
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 be quiet! SFX Power 3 |
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 Apevia SFX-AP500W |
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 FSP SFX Pro 450W |
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Check Latest Price |
1. Cooler Master V750 SFX Gold – the best all-round SFX PSU for mini-ITX
Cooler Master V750 SFX Gold ITX SFF Power Supply, PCIe 5.1 Ready
750W true SFX footprint
ATX 3.1 with 450W 12V-2x6
80 PLUS Gold and Noise A
10-year warranty
Pros
- True SFX footprint that fits the smallest ITX cases
- Fully modular short cables suit cramped layouts
- ATX 3.1 with a 450W-capable 12V-2x6 connector
- 80 PLUS Gold plus Cybenetics Gold and Noise A
- 10-year manufacturer warranty
Cons
- Bundled cable lengths are short so larger ATX cases may need extras
- Single cooling fan means acoustics depend on load
- Premium pricing versus comparable 750W SFX units
This is the unit we ended up recommending to almost everyone who asked. It measures 3.94 by 4.92 by 2.5 inches, which is genuine SFX sizing, so it drops into the tightest Mini-ITX enclosures without a bracket or a compromise. The 750W rating sits at the top of what most small cases can cool, which means you are not choosing between fit and capability.
The thermal design is the part that impressed us most. Cooler Master integrated the transformer, rectifier, full-bridge LLC stage and an EMI-inhibited amorphous metal structure, so the unit holds its 80 PLUS Gold rating inside an enclosure with almost no air path. The Cybenetics Noise A certification is a separate acoustic standard from 80 PLUS, and it is the one that actually predicts what you hear.
For a modern discrete GPU, the ATX 3.1 compliance matters more than any spec on the box. The bundled 90-degree 12VHPWR and 12V-2×6 cable delivers up to 450W straight to the card with no adapter daisy-chain in between. That removes the single most common source of trouble in compact gaming rigs.
One reservation: the cables are deliberately short. Cooler Master customises the lead lengths for small form factor routing, so if you move this unit into a mid-tower you will need extensions. Owners moving into ATX cases should read that limitation before ordering, not after.
What you get for the money
Ten years of warranty coverage on a 750W SFX unit is unusual in this category and is the clearest signal of how Cooler Master rates its own longevity. Combined with Gold efficiency and dual certification, it makes this the safest default choice for a first serious SFF build.
The cable bundle covers a 20+4 motherboard connector, 4+4 CPU power and the native GPU lead. A builder pairing this with a current-generation card gets a clean, single-cable-per-GPU layout that leaves room in the chassis for storage.
Where it falls short
There is only one cooling fan, and at this size it is a 92mm-class unit rather than the 120mm you get in an SFX-L body. Under a sustained heavy load the acoustics become load-dependent, so if your machine is going to sit in a living room and serve as a console, weigh the Corsair SF750 instead.
It is also the more expensive option in the 750W group, which is a fair criticism when the Lian Li SP750 V2 delivers comparable wattage, ATX 3.1 compliance and warranty length for less. You are paying partly for the acoustic certification and partly for brand confidence.
2. Corsair SF750 (2024) – the Premium Pick choice with Platinum efficiency
CORSAIR SF750 (2024) Small ATX 3.1 PCIe 5.1 750W Power Supply – Black
750W SFX
80 PLUS Platinum
Zero RPM fan-stop
ATX 3.1 and PCIe 5.1
Pros
- Exceptionally quiet with a zero-RPM mode at typical loads
- Platinum efficiency in a compact SFX body
- ATX 3.1 and PCIe 5.1 ready with transient spike resistance
- Fully modular sleeved cables simplify SFF cable management
- SFX-to-ATX bracket included
- Clean power with no reported coil whine in normal use
Cons
- Motherboard cable is roughly 17 inches which is short for larger cases
- Corsair does not sell a longer SFX-spec motherboard cable as a spare
The SF750 remains the reference point that most SFF builders compare everything else against, and the current model has been updated to the modern platform. It carries 80 PLUS Platinum efficiency, a 92mm fluid dynamic bearing PWM fan and a zero-RPM mode that stops the fan entirely at typical loads.
That fan-stop behaviour is the headline feature. On a Mini-ITX system that spends most of its life at a desktop, the power supply contributes no fan noise at idle whatsoever, which removes one of the three noise sources in a typical small build. Owners also report no coil whine in normal use, which matters more than most buyers expect.
On the electrical side, this unit is ATX 3.1 compliant with PCIe 5.1 support and transient spike resistance, and it uses 105C-rated Japanese capacitors rated to a 90C upper temperature environment. The fully modular Type-5 Micro-Fit connectors are a Corsair-specific design, so plan your cable routing around the shorter Type-5 leads.
Roughly 72% of ratings are five stars, which is a strong signal for a platform with this much history. The one recurring complaint is deliberate: the motherboard cable measures about 17 inches, which is short for anything larger than a small form factor case.
Where the silence actually comes from
Zero RPM is not the same as silent. It means the fan does not spin below a defined load threshold, so an idle machine makes no fan noise from the supply at all. Under gaming load the 92mm FDB fan takes over and stays inaudible at a distance in most enclosures.
Platinum efficiency adds a second, quieter benefit. Less energy becomes heat inside the chassis, so the fan spins less often and the case runs cooler overall. In a sealed sandwich-layout enclosure, that difference compounds.
The cable length problem
If your case is a compact micro-ATX sandwich layout or a Mini-ITX steel box, the short leads are a feature. They stop you from having to stuff a coil of excess cable somewhere it will obstruct airflow or a drive bay.
In a full ATX case they are a genuine limitation, and Corsair does not sell a longer SFX-spec motherboard cable as a spare. Measure your case before committing, because replacing the supply later means buying a different supply.
3. Lian Li SP750 V2 – the best value 750W with ATX 3.1
LIAN LI SP750 V2 750W SFX Power Supply, 80 Plus Gold, Black (SP750G.B)
750W SFX
ATX 3.1 with native 12V-2x6
80 PLUS Gold
10-year warranty
Pros
- Best price-to-wattage among the 750W options here
- Highest average rating in the roundup at 4.5 stars
- Built to the official 63.5mm SFX height specification
- Native two-tone 12V-2x6 cable for 50 and 40-series cards
- Quiet 92mm fluid dynamic bearing fan with fully modular cabling
- 10-year hardware warranty
Cons
- Gold efficiency rather than Platinum so more heat than top-tier units at similar load
- Smaller review base than the established SilverStone and Corsair models
Lian Li built their reputation on cases, so it makes sense that their power supplies are engineered around fit. The SP750 V2 is built to the official SFX size specification of 63.5mm, which is a detail more manufacturers are vague about and one that decides whether a unit physically drops into your chassis.
It is ATX 3.1 certified, supports the PCIe Gen 5.0 platform and resists transient power spikes, and it ships a native two-tone 12V-2×6 cable. The two-tone colouring is a small design decision with a real purpose: it gives you a visual cue that the connector is fully seated before you close the side panel, which is the most common cause of a failed GPU power connection.
Cooling is handled by a premium 92mm fluid dynamic bearing fan, and the cabling is fully modular. One underappreciated change from the previous generation is the standby rail, upgraded from 2.5A to 3A, which matters more in a modern build with several USB devices drawing from the 5VSB line than the spec sheet suggests.
About 80% of ratings are five stars, giving it the highest average in this roundup. The reason it is not our top pick is not quality; it is that Gold efficiency runs a little warmer than the Platinum units, and the review base is still small compared with the long-running SilverStone platforms.
Why efficiency tier matters more in a small case
Every watt that becomes heat instead of usable power has to leave the enclosure. A sandwich-layout case has very little exhaust area, so a Gold unit runs its fan harder and longer than a Platinum unit delivering the same wattage to the same components.
If your build lives in a quieter room, or runs 24/7 as a server, that difference is worth paying for elsewhere. For a gaming machine on a desk, Gold at this capacity is the sensible trade.
Known drawbacks
Gold efficiency is the main one, and it is a real cost: more heat in a confined space means more fan hours and slightly more noise under sustained load. Platinum units in this list cost more but run cooler.
The second is history. With 66 reviews, this model has a much thinner track record than the SilverStone and Corsair platforms here. Early sentiment is strongly positive, but early sentiment is not the same as five years of field data.
4. ASUS ROG Loki SFX-L 750W Platinum – the SFX-L showcase unit
ASUS ROG Loki SFX-L 750W Platinum (Fully Modular Power Supply, 80+ Platinum, Lambda A Certified, 120mm PWM ARGB Fan, Aura Sync, ATX 3.0 Compatible, PCIe 5.0 Ready, 10 Year Warranty)
750W SFX-L
80 PLUS Platinum
Lambda A below 25 dB
600W 16-pin cable
Pros
- Platinum efficiency at a lower cost than other Platinum SFX-L units
- Large 120mm axial-tech fan stays near-silent under sustained gaming load
- Native 16-pin PCIe 5.0 cable carries up to 600W
- Individually sleeved cables bend easily in tight SFF corners
- Aura Sync ARGB lighting syncs with motherboard software
- 10-year core warranty
Cons
- Bundled cables run long for compact SFF cases and may need re-routing
- SFX-L body is deeper than standard SFX
- RGB lighting is a premium feature some buyers will not use
The ROG Loki is the only SFX-L unit in this roundup that is explicitly a gaming product rather than a silent workstation one, and it makes no apology for it. It is 750W, 80 PLUS Platinum rated at up to 92% efficiency, and it is Lambda A certified for low noise below 25 dB.
The extra depth of the SFX-L chassis pays for itself in cooling. A 120mm axial-tech PWM fan moves far more air at a given speed than a 92mm fan, and ASUS places ROG heatsinks over the critical components so internal temperatures stay low enough that the fan rarely needs to ramp up. Under sustained gaming load, owners consistently describe it as near-silent.
For graphics cards, the bundled 16-pin PCIe 5.0 cable can deliver up to 600W, which means no adapter daisy-chain on any current or next-generation card. The unit is ATX 3.0 compliant, so it predates the 3.1 hold-up requirement but comfortably exceeds the power delivery needs of any SFF-class GPU.
Warranty coverage is 10 years on the core product with a separate 3-year warranty on the RGB LED elements, which is standard practice for any illuminated component. The Aura Sync lighting ties into the same motherboard software as the rest of an ROG build.
What the SFX-L body actually buys you
SFX-L is the same width and height as SFX, roughly 125 by 63.5mm, but deeper at about 130mm rather than 100mm. That extra 30mm is the entire reason this unit has a 120mm fan instead of a 92mm one, and a 120mm fan at a low RPM is dramatically quieter than a 92mm fan working hard.
The trade is a hard physical one. Your case must have room for the deeper body. Sandwich-layout cases and most Mini-ITX steel boxes do not, while larger small form factor chassis and many micro-ATX cases do.
Where it falls short
Cable length is the most common complaint. The bundled leads are longer than a compact case needs, so builders either re-route them carefully or shorten and re-pin them. This is the opposite of the Corsair and Cooler Master approach, which is deliberate on both counts.
The second issue is that the lighting is a feature you pay for whether or not you use it. In a plain office or a windowless rack, the ARGB is dead weight in the spec sheet. The third is case compatibility, which you should confirm before anything else.
5. SilverStone SX700-PT – the established Platinum 700W benchmark
SilverStone Technology SilverStone SX700-PT SFX 700W, High Efficiency with 80 Plus Platinum Certification
700W true SFX
80 PLUS Platinum
92mm FDB fan at 18 dBA
All Japanese capacitors
Pros
- True 700W Platinum unit in a compact chassis
- Very quiet 92mm fluid dynamic bearing fan with an 18 dBA floor
- Fully modular cabling for clean SFF builds
- Japanese capacitors and a single strong 12V rail
Cons
- Requires the separate PP08 bracket to mount in ATX cases
- Only a 1-year parts and labor warranty
- Weakest sales rank of the 700W options in this roundup
SilverStone invented the SFX category and the SX700-PT is the unit that established the benchmark for a quiet, Platinum-rated, fully modular SFX supply. It measures 3.94 by 4.92 by 2.5 inches and delivers 700W on a class-leading single 12V rail.
The cooling specification is where this unit separates itself. A 92mm fluid dynamic bearing fan with an 18 dBA minimum noise floor means the fan is designed to sit at the bottom of its curve for as long as possible. Fluid dynamic bearings also resist the bearing wear that turns into a buzzing noise after a year of operation, which is the failure mode owners complain about most on cheaper units.
All Japanese capacitors throughout, combined with Platinum efficiency, means less internal heat and a longer-lived design in an enclosure with minimal airflow. It is a straightforwardly well-built unit with no gimmick and no lighting, and for a workstation or a compact server that is exactly what you want.
One important note on longevity: this design predates the 12V-2×6 era, so on a modern graphics card you will be using the older 6+2 pin connectors rather than a native 16-pin cable. It handles demanding GPUs well, but the cabling is not future-facing.
Why 700W Platinum still makes sense
Platinum efficiency is worth more at lower wattage than at high wattage in absolute terms, but the ratio matters more than the total. At 700W with a 92% efficient design, the difference in waste heat versus a Gold unit is small enough that a well-ventilated small case handles either comfortably.
What 700W buys you is a 50W margin over a 650W-class recommendation, which is the buffer that covers a power-hungry CPU upgrade without a PSU change. That headroom is the real argument for this unit.
The warranty catch
One year of parts and labour coverage is the weakest warranty among the 700W options here, and it is a genuine gap when you compare it to 10 years on the Cooler Master and Lian Li units at similar capacity. A long warranty is partly a manufacturer’s confidence signal in the platform, and that signal is missing.
The second practical issue is mounting. This is SFX-only hardware, and ATX cases require the separately sold PP08 bracket. Confirm your case takes SFX directly before ordering, particularly if you might move the unit later.
6. SilverStone SX700-LPT-USA – the SFX-L with the biggest fan
SilverStone Technology SST-SX700-LPT-USA 700W, SFX-L, Silent 120mm Fan with 036DBA, Fully Modular Cable Power Supply SX700-LPT-USA
700W SFX-L
80 PLUS Platinum
120mm semi-fanless fan
24/7 rated output
Pros
- SFX-L depth allows a large 120mm fan for very quiet cooling at 36 dBA
- Platinum efficiency with 700W continuous output rated for 24/7 use
- Fully modular short flat-array cables keep SFF builds tidy
- Four PCI-E 8 and 6-pin connectors support heavily equipped systems
Cons
- Longer SFX-L body will not fit the tightest SFX-only enclosures
- Only a 3-year parts and labor warranty
The LPT version of the SX700 takes the 700W Platinum platform and gives it the SFX-L chassis so it can carry a 120mm fan instead of a 92mm one. Body depth grows to 5.12 inches, and everything else about the design philosophy stays the same.
That 120mm fan runs at 36 dBA in normal operation and supports advanced semi-fanless behaviour, so it stops entirely under light load and stays quiet when it does spin. A larger fan at a lower RPM is the single most effective way to reduce the noise of a small power supply, and this chassis is built to allow exactly that.
For systems that run continuously, the 700W output is explicitly rated for continuous 24/7 operation. Combined with 80 PLUS Platinum efficiency, that makes this a sensible choice for a home lab or a NAS chassis where the machine is on around the clock and every decibel matters.
Cabling is fully modular with short flat-array leads, which is a different design approach from the sleeved round cables used by Corsair. Flat arrays route more predictably in a tight space and avoid the snag hazard of a sleeve catching on a case edge. Four PCI-E 8 and 6-pin connectors cover a heavily equipped multi-GPU-style configuration.
Built for continuous duty
A NAS or home lab machine is on far more hours than a desktop. Fan bearing wear and capacitor stress both accumulate with runtime, so a unit explicitly rated for 24/7 continuous output with semi-fanless low-load behaviour is a meaningfully different proposition from a gaming supply of the same wattage.
The Platinum rating also reduces the sustained thermal load, which is the other half of long-term reliability in a sealed small enclosure.
Where it does not fit
The 5.12 inch depth is the entire problem. If your case accepts SFX only, this unit is physically too long, and there is no bracket or workaround that changes the body length. Check the case specification against the power supply depth before anything else.
The second limitation is warranty length: 3 years of parts and labour. That is better than the SX700-PT’s single year but well short of the 10-year coverage on the 750W units in this roundup.
7. SilverStone SX700-G – the budget 700W route
Silverstone Technology SST-SX700-G 700W SFX Fully Modular 80 Plus Gold PSU with Improved 92mm Fan and Japanese Capacitors.
700W SFX
80 PLUS Gold
92mm FDB fan at 18 dBA
Fully modular flat cables
Pros
- Best price-to-wattage among the 700W options in this roundup
- Very quiet 92mm fluid dynamic bearing fan with an 18 dBA floor
- Fully modular flat cables suit SFF cable management
- Japanese capacitors with strict 3 percent voltage regulation
Cons
- Gold efficiency rather than Platinum so it runs slightly warmer under equivalent load
- SFX mounting holes only and an adapter bracket is needed for ATX cases
The SX700-G is the same SilverStone SFX platform approach as the Platinum model, with the efficiency tier stepped down to Gold and the cost reduced accordingly. It keeps the parts that matter for acoustics: a 92mm fluid dynamic bearing fan with an 18 dBA minimum noise floor.
It also keeps the electrical fundamentals. All Japanese capacitors, a class-leading single 12V rail with strict 3% voltage regulation, and low ripple and noise. For most small form factor builds, the difference between a good 80 PLUS Gold supply and a good Platinum one is heat and cost, not output quality.
Cabling is fully modular with flexible flat arrays, which is genuinely the right choice in a cramped chassis. Flat ribbon-style cables take a bend, hold it and stay out of the way, where a round sleeved cable fights you the entire way into position. The 92mm fan keeps the same acoustic promise as the Platinum unit at a lower tier of conversion efficiency.
What you give up is heat. A Gold-rated unit turns a larger share of input power into waste heat, so in a sealed enclosure the fan runs slightly more often at the same load. The difference is small, but it is the reason we do not put this unit at the top of the list.
When Gold is the right call
If the case has any venting at all, and the machine is not a living-room console or a bedroom PC, Gold efficiency is entirely adequate. You get the same 92mm fan, the same Japanese capacitors, the same modular flat cabling and the same 700W of clean single-rail output.
The saving goes into a better graphics card or a larger case fan, which produces a bigger real-world improvement than the efficiency step does.
Limitations to know about
First, mounting. This is SFX hardware only and the mounting holes do not align with ATX patterns, so an adapter bracket is needed for larger cases. Budget for that if your build might move.
Second, it is the lowest 80 PLUS tier among the 700W SilverStone options here, which means marginally more internal heat and slightly higher fan activity under sustained load. If the build is going into a genuinely hot corner, spend the difference on Platinum.
8. be quiet! SFX Power 3 450W – built for silent low-power builds
Be Quiet SFX Power 3 450W
450W SFX
Fully modular
80mm low-noise fan
Under 1kg chassis
Pros
- Built for acoustically sensitive small builds under the be quiet! name
- Fully modular cabling in a compact SFX enclosure
- Lightest unit here at under 1kg and easy to mount in tight cases
- Consistently strong 4.4-star rating across owners
Cons
- 450W output is the lowest capacity in this roundup and limits GPU and CPU headroom
- 80mm fan is smaller than the 92mm and 120mm options elsewhere
be quiet! built this unit for one purpose: a small machine where acoustic output is the first design constraint rather than an afterthought. The 450W SFX Power 3 is fully modular, measures 3.94 by 4.92 by 2.52 inches, and weighs under 1kg, which makes it the lightest unit we covered and the easiest to install in a tight enclosure.
Approximately 70% of ratings are five stars, and the satisfaction pattern tracks directly with the acoustic design. In a build that is essentially a workstation or a low-power system where a discrete GPU is modest or absent, the fan simply never needs to reach a speed you can hear.
Two PCI Express connectors in 6+2 pin configuration cover the graphics cards that fit inside this power budget. For an integrated-graphics system, a low-profile card or a modest mid-range discrete card, that is the correct and complete connection set.
Where a 450W ceiling works
A 450W supply is appropriate when the graphics card is integrated or low-power and the CPU is an efficient, non-overclocked part. Think office desktops, home lab nodes, media servers, a silent workstation, or a Mini-ITX case that can only hold a small supply anyway.
The efficiency of buying low here is direct: you spend less on a unit whose fan never has to work hard, and the capacity ceiling is a non-issue because the system never approaches it.
Where the ceiling bites
Any modern discrete graphics card changes this calculation. Once you add a card that pulls 200W or more under load, plus a CPU that boosts hard, you have very little margin, and a supply running near its limit is a supply running its fan at a higher speed.
The 80mm fan is also the smallest in the roundup. There is no way to move a lot of air quietly with an 80mm fan, so the acoustic advantage here comes from the light load rather than from a large fan. Plan for that if your hardware list grows.
9. Apevia SFX-AP500W – a 500W starter unit with a wide connector spread
Apevia SFX-AP500W Mini ITX Solution/Micro ATX/SFX 500W Power Supply
500W SFX
Non-modular sleeved leads
80mm thermal fan
11 connectors
Pros
- Very low cost for a usable SFX unit
- Compact 125 by 100 by 63.5mm enclosure fits tight ITX cases
- Good connector spread with 20+4 main 4+4 CPU 6+8 PCIe 3x SATA and 2x Molex
- Split-able CPU and GPU connectors broaden motherboard and card compatibility
- Many owners report stable voltages with no failures on low-to-moderate draw systems
Cons
- Non-modular cabling makes cable management in small cases harder
- 80mm fan is the loudest in the case once it warms up with bearing noise on spin-up
- Limited headroom and not suitable for high-end power-hungry GPUs and CPUs
- Only a 1-year warranty
With 541 ratings, the Apevia SFX-AP500W has the largest review base of anything in this roundup by a wide margin, and the pattern in those reviews is consistent: buyers treat it as a deliberate entry-level pick for low-power ITX and office machines, and are usually happy within that frame.
The connector spread is genuinely good for the money. You get a 20+4 main connector, a 4+4 CPU connector, a 6+2 PCIe connector, three SATA and two Molex, and the split-apart options mean it works with older motherboards and simpler cards without adapters. The enclosure measures 125 by 100 by 63.5mm, which is exact SFX sizing.
Input is 115 volts only, which is worth knowing if you are outside North America. It is a single 80mm thermally controlled fan with air cooling, and the design is non-modular with sleeved leads.
Where a 500W starter makes sense
An office machine, a media centre, a first small form factor build where the graphics card is integrated or modest, and a strict budget all point the same direction. Owners report stable voltages and few failures on systems with a low-to-moderate draw, which is exactly the class of machine this unit is built for.
Fit-for-purpose is the honest description. This is not enthusiast-grade hardware and it is not trying to be.
Where it will disappoint
The recurring complaint is fan noise. The 80mm fan is the smallest and fastest-spinning in this roundup, and multiple owners report it becoming noticeably loud after a few weeks, with bearing noise on spin-up. In a case where the supply is the only moving part, that noise is the whole acoustic budget.
Non-modular cabling is the second issue and it is a structural one in small cases: you cannot remove the leads you do not need, so you route and hide the full bundle. The third is a 1-year warranty and limited headroom for any high-end GPU or CPU pairing.
10. FSP SFX Pro 450W – the office and APU budget option
FSP SFX Pro 450W Power Supply, 80 Plus Bronze Certified PSU
450W SFX
80 PLUS Bronze
DC-to-DC regulation
SFX-to-ATX bracket included
Pros
- Low cost for a 450W SFX unit well suited to office and budget builds
- DC-to-DC design gives better voltage regulation than typical Bronze-tier supplies
- Free SFX-to-ATX adapter bracket broadens case compatibility
- All-black ribbon cables blend into compact builds
- Fan speed control tied to PSU temperature keeps it quiet at idle
Cons
- Non-modular cabling is awkward to route in tight SFF cases
- 80 PLUS Bronze is the least efficient certification represented here
- 450W output restricts modern GPU and CPU upgrades
The FSP SFX Pro targets the simplest possible use case: a small office or entry machine that needs stable, quiet power and nothing more. At 450W with 80 PLUS Bronze certification it is the least efficient unit in this roundup, and the 4.0 average rating is the lowest, with 11% of ratings at two stars.
Two design choices lift it above a bare-bones supply. The DC-to-DC module design means voltage regulation and conversion are handled in the digital domain, which produces better rail stability than the older grouped-rail approach typical of Bronze-certified units. And the sleeved fan adjusts its speed to the power supply temperature, so it stays quiet at idle.
It also includes an SFX-to-ATX adapter bracket in the box, which is a practical inclusion that several of the modular units here do not offer. All-black ribbon cables blend into a compact build without the visual noise of coloured sleeving.
Where Bronze is acceptable
Efficiency only matters in proportion to how much power you draw and for how long. An office machine drawing 150W with a 450W supply runs at roughly a third of capacity, where the absolute difference between Bronze and Gold efficiency is a handful of watts of heat. That is not measurable in a small case.
The DC-to-DC design means you are not giving up voltage regulation quality, which is the thing that actually protects your components. For a system that is on eight hours a day doing office work, this unit does its job.
Where to look elsewhere
Bronze is the least efficient certification here, so under sustained high load the fan runs hotter and louder than a Gold unit would. Combined with 450W capacity, that makes it a poor match for any gaming configuration.
Non-modular cabling is the practical annoyance, and it is worse in a sandwich-layout case where every millimetre of routing space is contested. If your build needs any upgrade headroom, move up to a 700W Gold unit such as the SilverStone SX700-G.
SFX vs SFX-L vs ATX: Which Form Factor Fits Your Case
An SFX power supply is a compact 125 by 63.5 by 100mm unit built for small form factor cases, while an SFX-L is identical in width and height but roughly 30mm deeper at 130mm, and a standard ATX unit is 150mm wide and 86mm tall. The SFX-L extra depth exists for one reason: it allows a 120mm cooling fan where a standard SFX chassis only fits 92mm or 80mm, which is the single biggest lever on power supply noise.
The consequences are entirely about your case. Mini-ITX steel boxes and tight sandwich layouts usually take SFX only. Larger small form factor chassis and many micro-ATX cases with a full-length power supply bay accept SFX-L comfortably. A full ATX case accepts an ATX unit, and can take an SFX unit only with a bracket.
Below SFX sit two more tiers. TFX is smaller again at roughly 85mm deep but is now uncommon. Below that, PicoPSU units run in the 100 to 200W range and are used for ultra-thin APU-only builds where nothing else fits.
One practical warning from SFF builders: mounting brackets strip easily. The quarter-turn offset that lines the SFX screw holes with the case’s is easy to get wrong, and forcing a misaligned bracket strips the threads in the case panel. Start the thread by hand before using a screwdriver.
If you also work with lower-power hardware, our programmable DC supply roundup covers bench setups where the same efficiency logic applies at a different scale.
How Many Watts Does a Small Build Actually Need?
Wattage anxiety is the most common reason people oversize an SFX purchase, and oversizing costs you money you can spend on the graphics card. The defensible method is simple: add the GPU’s rated power draw to the CPU’s, add the rest of the system at roughly 50W, then add 30% headroom for transient spikes and future parts.
That method produces a number, and then you round up to the nearest SFX capacity that actually exists. Here is how it maps to real hardware classes.
A 450W supply suits integrated graphics, a low-profile card, or a modest discrete card with an efficient, non-overclocked CPU. This is the office, media centre and APU-only tier.
A 650W to 700W supply covers a mainstream mid-range graphics card with a mainstream CPU. This is the most common correct answer in the forum threads we read, and it is why the 700W SilverStone units have stayed relevant for years despite newer hardware.
750W is the practical ceiling for most SFX builds in 2026 and the sweet spot for a high-end card. Add about 350W of GPU, around 150W of CPU, 50W of everything else, and 30% headroom, and you land close to 700 to 750W.
For a 5080-class card, target 1000W or above, and in practice that means moving to an SFX-L or a full ATX unit rather than an SFX. There is no 1200W SFX power supply in this roundup, and the SFX class sits well below that ceiling. If your calculation lands at 1000W or more, the case probably has room for an ATX unit anyway.
One forum consensus worth repeating because it is correct: a 750W SFX unit is almost always enough for a Mini-ITX build, and a 600W Platinum-class unit can be sufficient for a lot of them. Buy for the hardware you have plus one upgrade, not for the hardware you might have in three years.
What ATX 3.1, 12V-2×6 and 80 PLUS Actually Change for You
ATX 3.1 is the current Intel power supply standard. For a small build it changes three practical things: it raises the required hold-up time to 12 milliseconds so the supply rides through transient power spikes from modern graphics cards, it requires native 12V-2×6 support, and it specifies transient response behaviour that prevents the shutdowns older units can cause under sudden GPU load.
The 12V-2×6 connector is the visible part. It is the successor to 12VHPWR and carries up to 450W on a single cable, which is why native support matters: a native cable removes the adapter daisy-chain that has been a persistent source of connection problems. The two-tone colouring on the Lian Li SP750 V2 cable is a visual seating cue for exactly that reason.
Native versus adapter is a real decision, and if your graphics card uses 12VHPWR, prefer a native cable and make sure it is fully seated before closing the case. If your supply predates the standard, an adapter works, but you are adding a failure point in the tightest, least accessible corner of the build.
80 PLUS certification describes how much of your AC input becomes usable DC rather than heat. Platinum units convert more than Gold units, which convert more than Bronze. The tier you should care about is the one that matches your load: Platinum for a quiet 24/7 machine, Gold for a gaming desktop, Bronze for an office box that idles most of the day.
One more term worth knowing is the PSU OEM, the manufacturer that actually builds the unit behind a brand name. Seasonic, Super Flower and Flextronics platforms underpin several well-regarded SFX models, and platform quality is a better reliability signal than the badge on the box. A Japanese primary capacitor rating, which appears on both SilverStone units here, is a second easy check.
Noise, Zero RPM Mode and Coil Whine
Small form factor builders talk about noise as one thing, but it is two, and they have different fixes. Fan noise is the power supply’s cooling fan spinning up because the unit is warm. Coil whine is a high-pitched electrical whine from stressed components under load. A quieter fan does nothing about coil whine, which is why the two must be evaluated separately.
On fan noise, zero RPM mode is the single biggest driver of perceived silence. It stops the fan entirely below a defined load threshold, so an idle machine contributes no supply noise at all. In this roundup the Corsair SF750 has an explicit zero-RPM fan-stop mode, and the SilverStone SX700-LPT offers semi-fanless operation at light load.
Beyond that, fan size is the lever. A 120mm fan in an SFX-L body moves far more air at a lower RPM than a 92mm fan in a standard SFX body, and an 80mm fan in a 500W unit has to work hardest of all. The ASUS ROG Loki is Lambda A certified below 25 dB, and the SilverStone units use 92mm fluid dynamic bearing fans with an 18 dBA minimum noise floor.
On coil whine, the honest advice is that you cannot predict it from a spec sheet. It depends on component tolerances, load and acoustic design of the entire case. r/sffpc owners report that a bundled Cooler Master 850 SFX in an NR200 Max was the biggest noise producer in their build, and that distinguishing the whine from fan noise was the first step to fixing it.
The practical test is simple: run the machine at a moderate gaming load in a quiet room and listen for a high-pitched tone separate from airflow. Then run it at idle and confirm the fan has genuinely stopped. If the tone is present in both states, it is coil whine, and the fix is a different unit rather than a different fan.
Replacing a bundled supply is also a legitimate route. If your case came with a 650W unit and you are moving to a quieter, more capable one, check the case warranty terms first, since replacing the included power supply voids coverage in some cases.
Cables, Brackets and the Mistakes That Bite Small Builds
The most destructive mistake in a small build is assuming modular cables are interchangeable. They are not. A modular SFX cable from one model will physically fit the socket on another and can destroy the supply. Each unit’s connectors are keyed to its own pinout, and mixing them across brands is the single most common hardware-killing error in this category.
Keep every cable that came with the unit, label them if you must, and never borrow a spare from another power supply in a drawer. If a cable is missing, replace the unit rather than sourcing a replacement lead.
Cable length is the second decision, and it goes in both directions. The Corsair SF750 and Cooler Master V750 ship deliberately short leads for tight routing, which means neither works well in a roomy ATX case. The ASUS ROG Loki ships longer leads, which means it can need shortening in a compact chassis. Match the supply to the case, not the other way around.
Finally, the bracket. ATX mounting holes do not align with SFX holes, so an adapter is required for an SFX unit in an ATX case. Some units include one, the Corsair SF750 among them, and some do not. Start the screw by hand, confirm the threads are engaged rather than cross-threaded, and never force it.
Our method for this roundup was straightforward: we kept only units that cleared live availability and had a rating of 4.0 or better with a meaningful review base, we dropped colour and model variants that duplicated an existing pick, and we excluded anything below 50 reviews. That is why the list is ten strong units rather than twelve padded ones.
For builders who also tinker with electronics at the bench, the variable bench power supply picks cover the other half of the power supply world.
Frequently Asked Questions
Which SFX power supply is the best?
The Cooler Master V750 SFX Gold is the best all-round SFX power supply for small builds, offering 750W in a true SFX footprint, ATX 3.1 compliance with a native 12V-2×6 cable, 80 PLUS Gold plus Cybenetics Noise A certification, and a 10-year warranty. For pure silence, the Corsair SF750 (2024) leads on Platinum efficiency and its zero-RPM fan stop.
What is the best affordable SFX power supply unit?
Affordability depends on capacity. At 450W for office and APU builds, the FSP SFX Pro is the cheapest route and includes an SFX-to-ATX bracket. At 500W, the Apevia SFX-AP500W has the widest connector spread in this roundup. At 700W, the SilverStone SX700-G delivers the best price per watt with a 92mm FDB fan and Japanese capacitors.
What is the best small form factor power supply?
For a compact SFF case the Cooler Master V750 SFX Gold is the strongest general answer, while the Corsair SF750 (2024) wins where silence is the priority thanks to its Platinum efficiency and zero-RPM fan stop. Below SFX, a 450W unit such as the be quiet! SFX Power 3 is ideal for integrated-graphics builds.
Is there a 1200W SFX PSU?
Not in practice for SFX form factor hardware. The highest-capacity SFX class tops out around 1000W, and nothing in this roundup exceeds 750W. If your wattage calculation lands at 1000W or above, plan on an SFX-L or full ATX unit instead, and confirm your case has room for the larger body.
Is an SFX power supply better than an ATX power supply?
No, not on quality. ATX units are generally cheaper per watt and easier to cool, but they physically will not fit many small form factor cases. Use SFX or SFX-L when case dimensions force you to, and an ATX unit with an SFX-to-ATX bracket when the case accepts either.
What is the smallest form factor power supply?
Below SFX and SFX-L, TFX measures roughly 85mm deep but is now uncommon. The smallest widely available option is a PicoPSU, which delivers around 100 to 200W and is used for ultra-thin builds with integrated graphics only. SFX at 125 by 63.5 by 100mm remains the practical floor for any system with a discrete graphics card.
Conclusion: The SFX PSU to Buy in 2026
For most small builds in 2026, the best SFX power supply is the Cooler Master V750 SFX Gold. It gives you 750W in a footprint that actually fits the tightest Mini-ITX cases, ATX 3.1 compliance with a native 450W 12V-2×6 cable, dual Gold and Noise A certification, and a 10-year warranty. There is no obvious weak point in it beyond cable length, and that is a deliberate design choice for the case it targets.
Buy the Corsair SF750 (2024) instead if silence is your first priority, and the Lian Li SP750 V2 if you want the same 750W class and ATX 3.1 spec for less. Go SFX-L with the ASUS ROG Loki or the SilverStone SX700-LPT only after confirming your case has the depth, because a larger fan cannot help you if the body does not fit.
Everything below 600W in this roundup exists for integrated graphics, office machines and APU builds, and those buyers should read the wattage section before spending more. Check the case dimensions, add the GPU and CPU draw, add 30% headroom, and pick the smallest unit that clears the result. That is the whole decision.