Question about power supplies concerning multiple 12v rails.

Toggle sidebar Toggle sidebar
W

WolfyB

Distinguished
May 23, 2012
39
0
18,540
I have a Raidmax 850w psu that supposedly has 4 12v rails rated for 34 amps each. From what I've read on the stickied thread on PSUs that means I have 61 amps total however I don't understand what the rails actually are and how people say you shouldn't put too much power on one rail. My PSU is modular so do certain slots on my PSU correspond to different rails inside or what? I just don't get how I'm supposed to avoid overloading one particular rail.

My current setup is:
i-5 3550
4 gigs of ddr3 ram
gigabyte z77-d3h mobo
1tb 7200rpm hdd
amd 6950 gfx

I just got the evga gtx 770 SC and before I plug it in I want to make sure that I have enough power. On the box it says it needs a minimum of 42 amps on THE 12v rail so I don't understand how that relates to my PSU since mine has more than one as well. I think my last psu shorted out from overload and killed two of my hdd's so I don't want to make the same mistake again.

Thanks in advance.
 
Sort by date Sort by votes
dark_globe

dark_globe

Splendid
Aug 16, 2013
1,187
106
26,390
don´t worry your psu has plenty of power...
even if it´s really multi rail design (sometimes just false advertising) manufacturer would certainly not put all the stress just on 1 of those rails ,
but rather split the power delivery for the system equally between them...
usually 1 rail is for cpu power , the others for the video card/cards
and the rest of the components like hard drives etc. needs only few watts of power ...
 
Upvote 0 Downvote
clarkjd

clarkjd

Splendid
Dec 7, 2005
6,486
34
28,490
The ATX standard says that you can only have so much current on a 12v rail, (20 amps, i believe), so when graphics cards started demanding more than that, PSU makers started using multiple rails, in order to limit the current on any one rail to the standard. Most multi-rail PSUs are really single rail models when you get into the internals of the PSU. Most modular PSU's do not allow you to select which rail is supplying the power.

That being said, We need more exact specifications for your Raidmax PSU (Model number, etc) in order to advise you. Raidmax buys PSUs from several different OEMs so the quality of it is suspect at best.
 
Upvote 0 Downvote
W

WolfyB

Distinguished
May 23, 2012
39
0
18,540


So the PSU automatically assigns power to certain rails so I don't have to worry about overloading one? That was my main question.



I provided the link to the newegg page at the beginning of my OP where it says "a Raidmax 850w psu". If you extend the gallery it has the chart showing the amps and whatnot as well. I'd also heard that Raidmax wasn't very good before but when my old one broke I kinda panicked and just bought one. Are they so bad that I should look into replacing it ASAP or is it ok? It has good reviews on Newegg so I figure its decent.
 
Upvote 0 Downvote
bignastyid

bignastyid

Titan
Moderator
Jun 19, 2011
33,486
1,619
159,590
I have never seen a raidmax PSU that was anything more than a pile of garbage. Did a bit o research and found its made by Andyson, uses the same internals as the Andyson AD-K850AE-D7 and the Ultra X4 750w. I couldn't find any reviews on the Raidmax or andyson, but I did find one on the Ultra, and not surprisingly it failed the review.
http://www.hardocp.com/article/2009/11/24/ultra_x4_850w_1050w_power_supplies_review/4#.Up9turQXfKE
So while it is a step in the right direction for Raidmax, its still not a PSU i would use.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom