Corsair SF850L SFX ATX 3.0 80 PLUS Gold PSU Review

TweakTown's Rating: 90%

The Bottom Line

Corsair continues its excellent reputation in the PSU market by introducing the SF850L. This SFX ATX 3.0 powerhouse will fit into many tiny places while providing plenty of juice to system components.

Pros

• + A good amount of cabling included
• + Very stable platform
• + 100% Japanese capacitors

Cons

• - 12VHPWR cable restricted to 300 watts

Should you buy it?

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Introduction, Specifications, and Pricing

Corsair, which oddly enough is not a stranger to the SFX PSU market, has announced two new SFX ATX 3.0 PSUs, the SF850L and the SF1000L. Upping the ante from the previous models, the SF600 and SF750, the SF850L, and SF1000L are Corsair's first SFX ATX 3.0 PSUs. Pricing for the two SFX ATX 3.0 PSUs are $179.99 and $199.99 respectively. Today we have the 850-watt model in for review, so let's check it out.

Corsair SF750 750 Watt SFX PSU

	Today	Yesterday	7 days ago	30 days ago
	$163.19	$134.29	$169.99	$169.99	Buy
	$169.99	$169.99	$169.99	$169.99	Buy
* Prices last scanned on 5/6/2024 at 6:27 am CDT - prices may not be accurate, click links above for the latest price. We may earn an affiliate commission.

Packaging

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The packaging on the SF850L is in the typical yellow cardboard box that Corsair is known for with its PC Components and peripherals.

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The backside of the yellow cardboard box has information like 80 Plus efficiency and Fan Curve graphs. The SF850L is rated 80 Plus Gold and Cybenetics Platinum.

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The side of the box in black with white lettering shows the cabling included with the SF850L. Only one 12VHPWR cable is included here, restricted to providing up to 300 watts.

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When we crack open the box, we are greeted with an important information pamphlet and a QR code on the yellow portion of the box. This QR code will lead the end user to the instruction manual.

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Removing the bag of cables shows a good amount of cabling included, even for an SFX PSU.

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Removing the cables from the bag is the 24-pin cable, 300w 12VHPWR cable, two 8-pin EPS CPU cables, three 6+2-pin PCIe cables, two SATA power cables, and a single MOLEX cable.

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Here is a closer look at the 300w 12VHPWR connector on the GPU side. Notice only two sense pins are present. Each sense pin is responsible for sending 150 watts each. Note the SF1000L model does have all four sense pins, thus allowing the full 600 watts of power.

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Corsair has decided to use two PCIe micro 8-pin connectors instead of another 12VHPWR connector on the PSU input side.

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Another good thing to see here is an SFX to ATX plate adapter included with the SF850L for those that like big cases and tiny PSUs.

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Finally, to the packaging of the SF850L itself, two dense black foam pieces protect the SF850L along with an opaque plastic bag.

Outside the Corsair SF850L SFX ATX 3.0 PSU

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The first thing I noticed when I removed all the packaging from the SF850L was this sticker, "Silent operation at low to moderate loads. In this mode, the fan will not spin." Corsair was getting a lot of RMA requests about dead fans; this helped resolve that issue.

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Shown here is the informational sticker side of the SF850L. The +12V rail has about 71 amps, while the +3.3V and +5V rails have 20 amps each.

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The fan intake side of the SF850L has a larger triangular ventilation fan grille; this helps with unimpeded airflow to the PSU components below. The Corsair sails logo is also embossed in the center of the fan grille. The back power input side has a single power rocker switch and more of the triangle ventilation pattern, along with the SF850L model name.

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Here is some Corsair branding along with the SF850L in larger white lettering.

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The Corsair sails logo is embossed in the center of the bottom of the SF850L.

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Inside the Corsair SF850L SFX ATX 3.0 PSU

The cable input side is laid out with Corsar's micro plugs. Notice the top writing "Designed for use with genuine Corsair type 4 cable sets only". Interesting.

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Cracking open the SF850L is Corsair branded NR1215. The NR1215 is a fluid dynamic bearing 120mm fan, running on 12V with .55A. Judging by the fin type and several fins, this fan is more airflow-focused.

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Now we get a good look at the innards of the SF850L. Corsair has chosen the OEM platform from Great Wall. How much power can be packed into such a small package still amazes me.

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Here is the main transformer used in the SF850L.

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The large capacitors from RubyCon, which is 100% Japanese made, are rated for 420V with 330µF and 420V with 510µF and are also rated up to 105C.

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VRM bank daughterboard generates power for the smaller 3V and 5V rails.

Test System

• Motherboard: B650I AORUS Ultra(AMD B650) - Buy from Amazon
• CPU: AMD Ryzen 9 7900 - Buy from Amazon
• Cooler: AMD Wraith Stealth - Buy from Amazon
• Memory: Corsair Dominator Platinum DDR5-7200 32GB - Buy from Amazon
• Graphics Card: NVIDIA RTX 3090 Founders Edition - Buy from Amazon
• Storage: Kingston Fury Renegade 1TB Gen4 PCIe x4 NVMe M.2 SSD - Buy from Amazon
• Case: Corsair 2000D Airflow mITX - Buy from Amazon
• Software: AIDA64 Engineer 6.32.5600, and CPU-z 1.94.0 x64
• Power Supply: Corsair SF850L 850w ATX 3.0 PSU - Buy from Amazon
• OS: Microsoft Windows 11 Pro 64-bit Build 22621 - Buy from Amazon
• Software: AIDA64 Engineer 6.8.6300, and CPU-z 2.03.0 x64

Testing & Final Thoughts

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For testing the SF850L, the mITX testing hardware used is a Ryzen 9 7900 12 core 24 threaded CPU on a B650i AORUS Ultra motherboard with 32GB of DDR5-7200 Dominator Platinum Edition from Corsair. An NVIDIA RTX 3090 FE was also used. Testing was conducted in a 22C ambient environment while running Aida64 Engineer's System Stability Test for 24 hours. Now in today's world, the entire system's power draw would always be, at most, the 850 watts that the SF850L offers. By staying within the 50% power threshold, the best efficiency, in this case, is at approximately 425 watts.

The test system pulled 432 watts from the wall, measured via a KillaWatt P3 electricity usage monitor; the test system reported 387 watts from all the components using CPUID HWMonitor. Doing some math, this makes the SF850L around 90% efficient, thus solidly earning its 80 Plus Gold and Cybenetics Platinum ratings.

Is the SF850L a worthy successor to the SF600 and SF750 models that came before it? Absolutely. The SF850L and SF1000L, while only a $20 difference between the two in pricing, the SF1000L has a 150-watt advantage. Looking at all the SFX PSU competition, which hovers in the $170 to $200 bracket, the two Corsair SFX PSUs are appropriately priced for their performance. The only thing to be aware of is the limitation of the 12VHPWR connection, which only provides up to 300 watts, so GPUs like the RTX 4090 might not be able to play.