Short answer: the Corsair SF Platinum (2024) is my pick for most small builds. Two lab reviews put it at the top of its class. If your case takes SFX-L, the ASUS ROG Loki Platinum goes up to 1200W.
SFX, SFX-L and ATX sizes
Check which size your case supports before anything else. These are the standard sizes. Some ATX units are longer than the figure here.
| Size | Width × height × depth | Typical fan |
|---|---|---|
| SFX | 125 × 63.5 × 100 mm | 80mm to 92mm |
| SFX-L | 125 × 63.5 × 130 mm | 120mm |
| ATX | 150 × 86 × 140 mm or longer | 120mm to 140mm |
SFX-L is the same width and height as SFX, just longer. That extra length fits a bigger fan, which can spin slower for the same cooling. If your case takes SFX-L, it's usually the quieter choice.
My SFX picks
- Best overall · Tier ACorsair SF Platinum (2024)80 Plus Platinum · Fully modular · SFX · 750/850/1000WHWBusters ranked it first among 850W SFX units and KitGuru gave it its top award. Comes with an ATX bracket.Check 850W price
- Platinum alternative · Tier ALian Li SP Platinum80 Plus Platinum · Fully modular · SFX · 850/1000WTier A, at 850W and 1000W.Check 850W price
- Gold alternative · Tier ACooler Master V SFX Gold (ATX 3.1)80 Plus Gold · Fully modular · SFX · 750/850WA Tier A SFX unit at 750W and 850W.Check 850W price
- 1000W SFX · Tier ASilverStone Extreme Rz Platinum80 Plus Platinum · Fully modular · SFX · 1000WTier A, for a high-power build in a small case.Check 1000W price
- SFX-L, high power · Tier AASUS ROG Loki Platinum80 Plus Platinum · Fully modular · SFX-L · 750/1200WTier A, available up to 1200W.Check 1200W price
- SFX-L at 850W · Tier ASilverStone Extreme R Platinum SFX-L80 Plus Platinum · Fully modular · SFX · 850WTier A, with the bigger SFX-L fan.Check 850W price
- Tier B option · Tier BThermaltake Toughpower SFX Platinum ATX 3.180 Plus Platinum · Fully modular · SFX · 750/850WPlatinum rated at 750W and 850W.Check 850W price
- Tier B option · Tier BASRock Phantom Gaming SFX80 Plus Platinum · Fully modular · SFX · 850/1000WA mid-range SFX unit at 850W and 1000W.Check 850W price
Which wattage for a small build?
Size an SFX unit the same way as any other. The wattage guide has the full tables. As a rough guide:
| Graphics card | Size | SFX pick |
|---|---|---|
| RTX 5070 or RTX 4070 | 650W to 750W | Corsair SF Platinum (2024) 750W |
| RTX 5070 Ti or RX 9070 XT | 750W to 850W | Corsair SF Platinum (2024) 850W |
| RTX 5080 | 850W | Corsair SF Platinum (2024) 850W |
| RTX 5090 | 1000W | Corsair SF Platinum (2024) 1000W |
Small cases get warmer inside, and a hot power supply runs its fan harder. A little extra headroom keeps an SFX unit quieter.
What to check before you buy
- Fan noise under load. Small fans spin faster. The SF Platinum is quiet at light and moderate loads, but KitGuru measured 37.4 dBA at its full 850W load.
- Fan direction. Check which way the fan will face in your case. Some small cases mount the power supply right next to the graphics card or side panel, and it needs space to breathe.
- Cable length. SFX cables are short. That suits small cases, but they may not reach in a bigger one.
- Cable stiffness. In a tight case, the bend of the graphics card cable matters. Leave room so the 16-pin plug isn't bent sharply near the socket. See the ATX 3.1 guide.
- Fully modular. Every SFX pick above is fully modular, so you only fit the cables you use. In a small case that matters more than usual.
Using SFX in a normal ATX case
You can fit an SFX unit in a standard case with an SFX-to-ATX bracket. The Corsair SF Platinum comes with one. It's a sensible option if you plan to move to a small case later, though in a big case the short cables can be a stretch to reach the top of the board.
Questions
Can I use an SFX power supply in a normal case?
Yes, with an SFX-to-ATX bracket. The Corsair SF Platinum includes one. Check the cables reach.
Will an SFX-L unit fit an SFX case?
Not always. SFX-L is 30mm longer, so check your case manual. Many small cases list both.
Are SFX power supplies louder?
Under heavy load they often are, because they use smaller, faster fans. At light loads many are silent.
Is 850W SFX enough for an RTX 5080?
For a typical build, yes. MSI recommends 850W for an RTX 5080 build.
Can I get 1000W in SFX?
Yes. The Corsair SF Platinum, Lian Li SP Platinum, SilverStone Extreme Rz and ASRock Phantom Gaming SFX all come in 1000W.
Sources
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