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Power Supply

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

( 4.8 Average / 38 Ratings )




Part #

(or) SS-850KM3
(or) SS-850KM-F3
(or) X-850 SS-850KM3 ACTIVE P
(or) X-850 (SS-850KM3 Active PFC F3)




850 W



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


Prices for this part are not available.

Price History (Excluding Tax) History:


thunderdan602 132 points 49 months ago
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.

RobertBel98 19 points 49 months ago
from completed build Client Build: 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.

Dhraiden 8 points 41 months ago
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!)

birkenpm 19 points 40 months ago
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.

hitstun 6 points 39 months ago
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.

bsmlk 8 points 33 months ago

This PSU might be overkill, but I did not skimp on the power supply in case she wants to upgrade the CPU/GPU in the future.

Volkov 11 points 26 months ago
from completed build Quicksilver RGB ( 1st Build )

80+ Gold, fully modular and got on super sale. Had a good review on Johnny Guru. More than enough wattage for now and down the road.

jalarson5 24 points 24 months ago
from completed build Penumbra v2

Great PSU. Looks good too, clean and nice. Super quiet, even under load, although the fan almost never turns on unless I am in BF1 or Tomb Raider. Even then, I can't hear it. Good venting and nice build quality. I probably should have gone with a 650W PSU since my PC doesn't even get close to 850W. First time builder's mistake! At any rate, you can't go wrong with this PSU.

iBeRobb 17 points 22 months ago
from completed build Ryzen from i5-3570k

Worth the money. Reliable and always started until some capacitors wore out. SeaSonic RMA process was quick and easy too. Got my unit fixed and sent back the same week I sent it in.

noseonarug17 11 points 20 months ago
from completed build Grawp

Eventually upgraded to this after getting a deal (no memory of what I paid, though). Works great, although my TDP is the same as before...my only complaint is that the cables aren't pretty and braided like my EVGA PSU.