Why would I need 2 rails for a PSU?

What can 2 rails do on a PSU that 1 rail can't do, and vice versa?
22 answers Last reply
More about rails
  1. Both can do exactly what is needed to be done. There is no advantage to 1 or multiple rail designs. In fact nearly all PSU use just 1 source for 12v, just split into separate rails.

    Link for good information:
    http://www.jonnyguru.com/forums/showthread.php?t=3990
  2. so ... I won't need it for somthing like SLI/CF?
  3. You will need a PSU that can power your system, plus 2 video card. The number of rails won't matter, as long as you have enough amp on the 12v source.
  4. So if I have 4 rails with each, say, 15A, then I can get the same as 1 rail with 60A?
  5. Single 60A rail is preferable
  6. >_> why?
  7. I am basically considering out of 2 PSU's. one with a single 12v rail at 52A and one with three 12v rails with 19A. Which one is better, if any, and why?
  8. 1) what are the PSUs...we can tell u based on Manufacturer

    2) the whole Single rail vs. multiple rail is all basically a gimmick. Some say that multiple rail gives overvoltage protection....single rail gives more power. Its all fake because most PSU that are "multiple rails" come from a single rail anyways..they just artificially split it.
    Exceptions of this are the Thermaltake 1000/1200 and Corsair HX 1000 (as examples). When u open them, they literally look like 2 separate PSUs, and provide 2 separate rails.

    So...just link the psus and well show u
  9. Coolermaster Real Power Pro 650WATT

    Corsair TX650W

    I am not expecting to get 3 completely different 12v rails with the coolermaster. I know that it is split at the end.

    Personally I prefer the Coolermaster one, and that's the one I'm gonna go with. Unless you can convince me with a good reason not to.
  10. Sure

    Ill convince u
    CM has an iffy rep when it comes to PSUs...they dont use the best parts

    The Corsair on the other hand is an amazing, Seasonic OEM PSU. They always use top notch parts, Nippon, Rubycon...u name it. Plus they are high rated Caps at 105C which is awesome. Great buy imo and more superior to the CM.
    Plus the PCIE on the Corsair are 6+2 so u can use them as 8 pin for newer GPUs and one that are coming out where as the CM has only 6 pin so u will need an adapter
    Lastly, i just love Corsair support...theyre amazing (not that ull need it with that PSU)
  11. ^oh jesus i didnt even see that CM only has 6 pin PCIE. damn ... good thing u told me! and the rest of the stuff u said is even more convincing! damn ... thanks man. I really appreciate the help. Looks like ill go with corsair, single rail!
  12. Yea i read WAY too much about PSUs, and Corsair has amazing rep in all respects but especially in the PSU department. (as well as RAM :P)

    But Corsair does use the best of the best.....and thats a fact
    CM changes depending on Model...and i just dont remember which are the good ones
  13. Silverion, I've done a ton of reading on PSUs lately, and from what I gather, Silverstone, Corsair, and PC Power & Cooling are top dogs when it comes to quality parts: your thoughts?
  14. hmmm lets see.....

    Silverstone: Some tend to be very good (Zeus, OP etc.)....others tend to be "okay". They arent going to blow up on u in the least bit but in some price ranges there are better choices at times.

    Corsair: All their PSUs are solid. Good parts for sure. Nothing else really needed to say

    PC P&C: Always good and trusted (Use Seasonic OEM if I'm mistaken)

    Others that are very good:
    Antec Signature: have one myself....expensive but top notch
    Thermaltake Toughpower >750: use the same CWT OEM like Corsair 750/850/1000
    Seasonic: Great manufacturer all around (OEM of Corsair 650 and below)
    and also from looks the Zalmans are good

    Those are all PSUs I'd use and just judge them based on Modular or not, and Price comparison....
  15. how important would you say is it for a PSU to be modular?
  16. Modular PSU's are a little bit of a gimmick tbh - just introduces another potential point of failure…

    Just get the Corsair TX650 – it’s amazing quality

    Or if you’re feeling flush how about the new TX850 – it would run just about anything and I have to say it’s probably the best PSU out there IMHO… http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=126
  17. hmmm I think I've decided. TX650 is the way to go
  18. Vixe said:
    how important would you say is it for a PSU to be modular?

    Modularity is a feature only important to the buyer and thats all....
    Doesnt affect the PSU really, its just, does the builder feel like dealing with all those cables.

    I always buy modular (or semi-modular for the Signature) because i like a clean case
  19. ok wait ... my topic still isnt answered. Why would I need 2 rails for a PSU? Why do they split the rail at the end? Why don't they just make a single rail if it is the same?
  20. Depends on the PSU...like the one u showed its really one rail split into 2 or however many, 3,4,8 w/e
    Really its to stop overvoltage protection. If one rail is overloaded too much the psu shuts down for protection. Generally this is done by setting a limit on the rail, 18A, 24A w/e the specs are. But as some PSUs show they dont even have this limitation like in a review of the Corsair 520HX. He raised one rail above the supposed "18A" and nothing happended.
    In a TRUE dual rail PSU (Corsair HX1000), u basically just have 2 separate PSUs powering 2 separate rails. Its all basically for protection/gimmick

    Here u can read this...Single vs. Multiple from the Pro
  21. Makes way more sense. You really know a lot about this :P anyways. thanks a lot for your help.

    You seem to know a lot about computers, so can you please check here what my build is going to look like. The general idea of what I am going to build is over there. If you can give me advice, criticism, anything... I would greatly appreciate it.
  22. Pmed

    And the PSU thing....all OCD. I wasnt sure what to get for my computer :kaola:
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