Head-to-head · Best 850w Power Supplies

Corsair HX850 vs Seasonic Focus PX-850

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

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The short answer

Seasonic Focus PX-850 comes out ahead by a clear margin (4.6 vs 4.9). The gap is mostly about fit for purpose — read the strengths below before deciding.

Ranked #2 in Best 850w Power Supplies

Corsair HX850

4.6

3 sources2 derived$311as of Aug 1

The Corsair HX850 is an 80 Plus Platinum, fully modular 850W unit whose defining trait is silence: ZeroRPM keeps the 135mm fan stopped until load demands it. KitGuru points to the Japanese 105°C capacitors and the build quality behind the ten-year warranty, and PC Perspective's bench work found voltage regulation on the main rails inside tight tolerances. The complaints are practical rather than electrical — thick ATX, EPS and PCIe cables that fight small cases, and over-current protection behaviour on the 5VSB rail. It suits a quiet high-end build where cable room is not the constraint.

Strengths

— Full power at 46°C ambient temperature
— 90% efficiency at real-world load conditions
— ZeroRPM mode for fanless operation at low loads

Watch-outs

— OCP at 5VSB
— Bulky ATX, EPS and PCIe cables

$311 · Buy at newegg.com Full review →

Higher ratedRanked #1 in Best 850w Power Supplies

Seasonic Focus PX-850

4.9

3 sources$413as of Aug 1

The Seasonic Focus PX-850 is a Platinum-rated 850W unit that runs efficiently and holds up over time. RelaxedTech praised the fully modular design, the high-grade Japanese capacitors, and the Fluid Dynamic Bearing fan with customizable cooling modes. A single +12V rail handles 70A, and the 10-year warranty puts it ahead of most competitors. At around $140 the price is competitive but still above budget alternatives. Enthusiasts and professionals who want premium build quality and long-term reliability should buy; budget-conscious users can find better value.

Strengths

— 80+ Platinum efficiency rating with 92% efficiency at 50% load
— Fully modular design with flat black cables for improved airflow
— Fluid Dynamic Bearing (FDB) fan with three operational stages: Fanless, Silent, and Cooling Mode

Watch-outs

— Price is still higher than budget Gold-class alternatives, even though it undercuts rival Platinum units by $20-$40
— Small 140mm footprint may not fit all cases with tight space constraints

$413 · Buy at newegg.ca Full review →

Derived means the reviewer published no score, so one was inferred from their written verdict. Everything else is a number the publisher printed. How we rank.

Specs side-by-side

Spec	Corsair HX850	Seasonic Focus PX-850
Wattage	850W	850W
Efficiency	80 Plus Platinum	80+ Platinum
Form Factor	ATX	Intel ATX 12 V
Modularity	Fully Modular	Fully Modular
Fan Size	135mm fluid dynamic bearing	120mm FDB
Warranty	10 years	10 Years
Compliance	ATX12V v2.4 and EPS 2.92 standards	Energy Star, RoHS, WEEE, ErP Lot 6, REACH
Connectors	2x EPS, 6x PCIe 6+2 pin, 16 SATA, 1x FDD, 1x ATX	20+4Pin, 2 x 4/8 Pin CPU, 6 x 6+2 pin PCIe, 10 x SATA

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