How to tell the rails apart?

xXaNaXx

Gawd
Joined
May 15, 2003
Messages
935
i just had my last power supply for my "Main Rig" in my sig below pop on me this thursday, and i don't have a lot of money at the moment for a replacement (the old one is out of warranty, so that's a no-go). anyway, i ordered an Antec BP550 Plus 550W for the time being (which will later be moved to the "Server Rig" in my sig when i can afford a better PSU for my "Main Rig").

but i got to looking at it, and noticed that i could not find anywhere that explains which connectors on the PSU are powered by which rails (there are 3x 12v rails). the sticker on the side doesn't explain it, nor does the manual i downloaded from the Antec site....it wouldn't be as important, but one of the 3 rails has a different amp rating (25a vs. 22a on the other two). does anyone know how i can find which connector is rated at 25a?
 

p3sty

2[H]4U
Joined
Feb 22, 2006
Messages
2,374
Doctor I believe its time to open that baby up. Or try to get a schematic.
 

xXaNaXx

Gawd
Joined
May 15, 2003
Messages
935
i don't have it just yet, it's due to be delivered today....but anyway, i'd rather not open it up, since that would void the warranty on it....which i don't want to do on a brand new PSU.

although, i guess if someone could tell me the amperage requirements for my video card (MSI NX8800GT 512MB OC GeForce 8800 GT @ stock (660/950), it'd be a moot point anyway....that's mainly what i'm trying to figure out, if the video card will be the one that gets 25a, or if it will be the mobo/CPU/RAM/etc.
 

shadow_419

Gawd
Joined
Apr 10, 2006
Messages
602
On multi-rail psu's it's usually broken down into cpu 12v, pci-e 12v, everything else 12v.
 

JoeBob

Limp Gawd
Joined
Jan 8, 2007
Messages
391
My guess is

12V1: CPU
12V2: Mobo + peripheral connectors
12V3: PCIe connectors.

This by looking at the rail distribution on the EA650. Review at jonnyguru.com, scroll to bottom

Edit: Your 8800GT will probably pull at the very worst, only 100W. That will be divided over 12V2 and 3. You could even add another 8800GT and still be well within limits.
 
Last edited:

Zero82z

Fully [H]
Joined
Jan 20, 2004
Messages
27,897
Without proper documentation, there's no way to know what the rail distribution is without opening up the PSU and following the traces. However, the good news is that modern PSUs have their rails pre-balanced, so that it's basically impossible to overload any single rail unless you have a really abnormal PC. So my advice to you is simply to not worry about it, since there's no way that your rig will even come close to triggering the OCP on any of that PSU's rails.
 

xXaNaXx

Gawd
Joined
May 15, 2003
Messages
935
hmmm....i guess i got a bit ahead of myself.....the photos on Newegg didn't show it, and there was nothing about it in the owner's manual, but once the PSU arrived, there was another sticker on it showing which connections were which rails.

got it all up and running now, it's working great
 
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