Corsair SF850L PSU review: small size but few of the drawbacks
We see if this SFX-L power supply from Corsair is worth the money
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The Corsair SF850L was released in 2023 as a new smaller-sized power supply that came with the latest ATX 3.0 and PCIe native support. This SFX PSU (or SFX-L to be more exact: the slightly bigger version) is a more compact unit for mini-ITX cases or similar, that seeks to retain a lot of the functionality and performance of the larger models. Let’s see how it holds up!
- Wattage: 850W
- Modularity: Fully modular
- Efficiency rating: Gold
- Compliance/compatibility: ATX12V v3.1, PCIe 5.0, EPS 2.92
- Dimensions: 125 x 65 x 130mm
- Weight: 1.13kg / 2.49lb
The Corsair SF850L is a great, energy efficient, small form-factor PSU that sacrifices very little in exchange for its more compact design. Unlike most SFX/SFX-L units it doesn’t cost much more than the ATX variants and comes with a nice spacing of connectors, plus has the benefits of an ATX 3.0 and PCIe 5 native connection; the 7 year warranty is reasonable. It’s certainly louder than average, but if you can get over that then there’s little reason not to buy it.
- Great energy efficiency
- ATX 3.0 standard & PCIe 5.0 connection
- Reasonably priced for an SFX PSU
- Decent 7 year warranty
- A bit on the louder side
Pricing
When it was originally released in 2023 the Corsair SF850L had an MSRP of around $180, with the larger 1000W variant SF1000L retailing for $200. Prices have come down a fair bit since, though equally it’s a bit difficult to find one new on Amazon (and second-hand models don’t have a transferable warranty). You can pick a new model up on BestBuy for around $149.99 at the time of writing, which is about $20 more than the ATX-size Corsair RM850e released in the same year. Generally you expect the mark-up on a smaller-size power supply to be higher than this: the price you pay for the compact design, and the current price compares very favourably to similar offerings from other brands.
Design
The PSU is built to the ATX 3.0 standard, which makes it ideal for full stability with the latest 40-series GPUs. It also supports PCIe 5 connectors and is cooled by a single 120mm fluid dynamic bearing fan.
Despite being a smaller-sized PSU, the SF850L gets by without cutting out much compared to your standard ATX, which is nice to see. You get plenty of connecting cables and ports, including a 12VHPWR connector, EPS/ATX 12V 8-pin cable for any overclocking or high-end motherboards, plus four PCIe 8-pin connectors, meaning you can easily connect to a high end GPU and CPU and have connections to spare. It comes with Type 5 micro fit cables and has full modularity.
Additionally, although it’s a smaller size, the sockets for the connections are well spaced out, not bunched together like you often see, which again helps during the building/upgrade process.
Aesthetically it’s your standard Corsair fair: all black with the white Corsair sails logo and lettering.
Size & compatibility
As mentioned the SF850L has an SFX-L form factor, which is essentially a slightly longer SFX size, though still very suitable for mini case builds. It does also come with an adapter to help it fit larger cases if need be as well.
As always, we’d recommend that you get accurate measurements of your case before purchasing anything to make sure the PSU definitely fits. Specifically, the Corsair SF850L measures: 125 x 63.5 x 130mm.
Sound & efficiency
There are two main rating standards when it comes to the efficiency rating of a PSU: the 80 Plus standard that’s been used for over the last decade, and the newer Cybernetics Labs standard, which is increasingly popular because it takes into account regional variations in mains power outputs, plus greater accuracy overall.
Usually both of these standards will end up rating the same PSU within the same broad category, however in the case of the SF850L it’s designated gold under the 80 Plus standard and platinum under Cybernetics Labs, both of which are good of course (though platinum is better).
Looking at the details of the Cybenetics tests, when measured at 115V of output the average efficiency came in at 90.577% with the 5VSB efficiency measuring 83.657%. When measured at 230V the PSU scored an average of 92.33%, with 83.020% for the 5VSB rail.
In terms of sound output, the SF850L is a bit louder than average, though certainly not unbearable. It has an overall Cybernetics noise rating of Standard+, an specifically scored an average of 36.09dB(A) at 115V, and 35.92sB(A) at 230V.
Warranty & Support
The warranty on this particular Corsair PSU is for 7 years, which is a bit shorter than what we’re used to for other gold/platinum rated power supplies by this brand, which often last for 10 years, however it’s still plenty long enough in our book. For the vast majority of custom PC builders, you’ll likely be looking for an upgrade by the time the 8th year rolls around anyway, so this length of coverage should offer piece of mind.
Corsair SF850L PSU
