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Power Supply

SeaSonic X Series 850W 80+ Gold Certified Fully-Modular ATX Power Supply

( 4.8 Average / 36 Ratings )





Part #

(or) SS-850KM3
(or) SS-850KM-F3




850 Watts





Efficiency Certification

80+ Gold


+3.3V@25A, +5V@25A, +12V@70A, -12V@0.5A, +5Vsb@3A

PCI-Express 6+2-Pin Connectors


Completed Builds Using This Part

See All Completed Builds


Merchant Base Promo Shipping Tax Availability Total
Newegg $124.99 -$15.00 +FREE s/h In stock $109.99
$15.00 mail-in rebate
Amazon $124.99 Free two-day shipping with Amazon Prime In stock $124.99
( 15 new from $114.95, 7 used from $89.99. Last updated 18 hours ago. )
SuperBiiz $129.99 $129.99+
NCIX US $131.99 In stock $131.99+
OutletPC $134.33 $134.33+
B&H $139.99 +FREE s/h $139.99
Mac Mall $172.99 +FREE s/h $172.99
PCM $174.99 +$16.96 s/h $191.95
* Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.

Price History (Excluding Tax & Combo Deals) History:


from completed build Desert Thunder

Tier 1 rated Seasonic X Series X-850 850W 80 Plus Gold Certified Full Modular PSU. It’s whisper quiet, it comes with a 7 year warranty, and is more than enough for what I need right now. And if i should decide to SLI in the future, I should still be fine. The cables are nice and long (no problems reaching components in my new full tower case) and come in nice storage bags. This was the first PSU I have ever used that comes with flat cables.

from completed build Client Build: Operation Blackbird

The SeaSonic 850W was chosen for its reliability, and 80 Plus Gold rating. And frankly guys, in my experience, you can never go wrong with SeaSonic.

from completed build Cerberus

This power supply has been a breeze to work with. Handles all of my components without a problem, and has been entirely silent.

from completed build My Current Gaming build.

Tier 1, 850w, overkill, but it'll work forever.

from completed build My current build. V2

Best PSU on the market.

from completed build New Rig Fall 2015

Another great deal - new, but lacking original packaging, from Amazon warehouse. Anxiously waiting months to complete build to see if it worked, but happily, it did. Invested in a PSU tester, but the cables were incompatible (always a good idea if getting non BNIB PSU's, though!)

from completed build Freesync Beast of Burden

if you install this upside down.. with the fan pointing down in a modern case.. this baby shows you the ugly side, which technical stickers and the like. plus the logo on the back will be upside down as well.. :/ really less than ideal. also documentation kinda sparse.

from completed build Red Cyclone

The SeaSonic 850W PSU was easy to install and hasn't missed a beat. It's a shame nobody can see this tidy modular wiring through my case's tinted side window.

from completed build Alpha

The best PSU money can buy. Very stable and modular. I really love it.