Seking satisfactory answer to tripple rail PSU question.

Yes I can google it, but I didnt seem to find an answer I was comfortable with. I am about to buy another one of this big power hungry monolithic graphics cards (sorry no room for SLI) , I have an antec TP3-650

it says it has 3x 12 volt rails rated for 19 amps each.

how do they add up? I know that with a dual rail PSU both 12 volt rails connect to the card, fine, but with 3 rails do all 3 still connect? do I get the power of all 3 rails to each card or do I just get two? how do I know that my components are working from all 3 rails and not just overworking one?

I understand that the high power cards feed from 2 rails but will they also feed off all 3? I don't understand if this implies 3 separate external connections each with its own internal circuit or just describes the internal design of the PSU where all 3 12v rails have a common bus or something.

I am about to buy a GTX 275 but I want to make sure that my 9800 GX2 didn't die because my PSU was doing strange things trying to power it

(I had a card die in the past because my PSU would raise the voltage to dangerous levels during periods of high load but now my mobo does not have good monitoring so I'm not sure anymore)

I'm not asking if the card and PSU is a good combo, the answer seems to be yes, but I want a satisfactory explanation as to why.

(this is the main reason I am asking in a power supply forum and not a graphics one)

anyways , thanks in advance for being patient, someone firing off "yes it will work" just isn't enough for me right now since I've been battling with this GX2 for a long time now and it's finally died, it had a terrible overheating problem. even when under clocking sometimes by as much as 50% probably fried its self to death. (GPU temps of over 100C etc)

and yes I did void the warranty on the 9800 (EVGA) and I forgot to register it anyways, I AM NEVER GOING TO MAKE THIS MISTAKE AGAIN
3 answers Last reply Best Answer
More about seking satisfactory answer tripple rail question
  1. Best answer
    AntecTPT Review
    Pay close attention to the end of page 2
  2. And if that's not enough for you, here is a link to a detailed explanation about mutiple 12 volt rails that are typically just one large mutiple rail:
  3. delluser1 said:
    AntecTPT Review
    Pay close attention to the end of page 2

    :na: *squint*

    oshi.... wow.... yeah I thought I took a good look, I guess not, thanks a lot. this is exactly the information I need! :o

    you'd think it was 3 bloody circuits the way they talk about it!

    this is some black magic EE/marketing BS I think.... :heink:

    I THINK I know just enough about wiring to know its a good idea to branch early rather then later so it does sort of have 3 "rails" I've seen this layout before in household, automotive and also aircraft wiring even when there is no circuit breaker (I'm an aircraft mechanic by trade) there are some wire/resistance/capacity reasons why running parallel wires from the PSU can be a bit better, wire resistance will cause a small voltage drop on each leg in a series circuit (remember the wire is the resistor-in-series not the components!!!) so if you go PSU----HDD1----HDD2----CDR where each connector has a wire going into it and then out again to the next connector the components would be in parallel with each other but the WIRES are in series so there would be a little voltage drop getting worse as you go down the line, but if you branch off from a common bus the voltage drop will be much more similar for each leg and have more to do with the load of each component assuming equal length wire.... you could even say the circuit becomes more parallel and less series..... also if one wire blows up it takes out less components at a time. using more/smaller wires will mean they will blow up at a lower load, thus doing less damage in the process (a small wire is a less capable heating element while it blows) , even if there ins't a fuse in each leg the wire kind of acts like a fuse, the reason big wires are dangerous is not because they "have more amps" but because they can take more abuse before they blow. so it's also a bit of a safety feature.

    in basic theory they teach you to treat wires as if they had zero resistance (in circuit diagrams etc) electrical engineers know better. and salespeople will say *anything*

    honestly I'd say the difference is probably PRETTY SMALL but hey if something is 1% better then you can list it as a FEATURE on the box! WOO!. and the difference (for safety and stability) will increase with wattage because it gets more and more unreasonable to carry high amps on a single wire as wattage goes up.

    making for some confusing bull****

    anyways, I'm going to smoke something, go to sleep and try not to dream about why EEs do the things they do and why salespeople say the things they say. peace :sleep:

    and yes I did order a BFG 275 OCX after all, aswell as a fairly cheap/pathetic CPU upgrade (phenom X4 9500 2.2ghz from Athlon 64 X2 4400+ 2.3GHZ ... so I can double my bogoflops and probably break even on single thread stuff... maybe I can calculate digits of PI or find aliens faster though.


    I will try to dream about THAT instead.
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