Originally Posted by microman
5 12v rails= FAIL
Originally Posted by Thunderer
Why it is a fail???
Originally Posted by microman
there is good and there is better and as most of us know a single 12v rail is the way to go.
Originally Posted by 003
misinformed masses, on both sides of the fence.
microman: I'm curious as to where you get your information from, because that source needs to be sent into exile.
What is "multiple +12V rails" really:
In most cases, multiple +12V rails are actually a single +12V source just split up into multiple +12V outputs each with a limited output capability. There are a few units that actually have two +12V sources, but these +12V outputs are either combined into one or split into four or more. To be clear: These REAL multiple +12V rail units are very rare and are all 1000W+ units (Enermax Galaxy, Topower/Tagan "Dual Engine", Ultra X3 1600W, etc.)
Do multiple +12V rails give me "better stability", etc:
Nope. Not at all. The components that spilt up the +12V into multiple +12V rails doesn't do any kind of regulation, filtering, etc. They just split the source up into two, four, six, whatever +12V circuits and has a logic that "shuts down" the PSU if any of the circuits exceed a particular current.
So why split the +12V rails up?:
Well.... 240VA+ is a lot of power. Some shorts aren't always detected by short circuit protection if there's enough resistance in the load. These "slow burn" shorts are enough to melt insulation and cause a small fire.
Why do some people FUD that single is better?:
Because a while back, some PSU companies followed EPS12V specifications, which is for servers, not "gamers", for quad +12V rail PSU's and put ALL of the PCIe connectors on one of the +12V rails. The +12V rail was easily overloaded and caused the PSU to shut down. Instead of correcting the problem, they just did away with the splitting of +12V rails altogether. Multiple +12V rail "enthusiast" PSU's today have a +12V rail just for PCIe connectors or may even split four or six PCIe connectors up across two different +12V rails. The rails themselves are capable of far more power output than any PCIe graphics card would ever need.
But some people claim they can overclock better, etc. with a single +12V rail PSU:
B.S. It's a placebo effect. The reality is that their previous PSU was defective or just wasn't as good as their current unit. If the old PSU was a Coolmax with four +12V rails and the new one is a PCP&C with one +12V rail, the new one isn't overclocking better because it's a single +12V rail unit. It's overclocking better because the old PSU was crap. It's only coincidental if the old PSU had multiple +12V rails and the current one has just one. The only "problem" with multiple +12V rails is that when they have a +12V rail overloaded, the PSU shuts down. Since there are no "limits" on single +12V rail PSU's, you can not overload the rails and cause them to shut down..... unless you're using a "too-small" PSU in the first place. Single +12V rails do not have better voltage regulation, do not have better ripple filtering, etc. unless the PSU is better to begin with.
Good thread on the matter: http://www.overclock.net/power-suppl...ails-work.html
Pay particular attention to DuckieHo's drawings.
The Enermax Galaxy has two +12V sources. One is split into two for the CPU via each of the 4-pins in the 8-pin EPS12V connector. The other is split into three. One powers the +12V on the 24-pin and one of the PCIe. Another powers all of the fixed Molex connectors and a second PCIe. The third supplies power to the modular interface.
Only 17A per rail, but plenty of power if you use all of the fixed cables first. If running dual cards that require two power connectors, you just use one fixed and one modular cable on each card.