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?

so ... I won't need it for somthing like SLI/CF?

So if I have 4 rails with each, say, 15A, then I can get the same as 1 rail with 60A?

>_> why?

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

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)

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 )

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

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....

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.p [...] 4&reid=126

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

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

Pmed

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