Very good article by Jonny Guru about Single vs. Multiple +12V rails:

[trt740]

Hes say that one is really no better than the other what do ya think.

Single vs. Multiple +12V rails: The splitting of the +12V rail

http://www.jonnyguru.com/forums/showthread.php?t=3990


excerpt this is only a small part of what he said and the two statement are not in the order they were printed. So read the whole thing yourself


1. In most cases, multiple +12V rails are actually just 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 are typically very high output power supplies. And in most cases these multiple +12V outputs are split up again to form a total of four, five or six +12V rails for even better safety. To be clear: These REAL multiple +12V rail units are very rare and are all 1000W+ units (Enermax Galaxy, Topower/Tagan "Dual Engine", Thermaltake Tough Power 1000W & 1200W, for example.)

In some cases, the two +12V rail outputs are actually combined to create one large +12V output (Ultra X3 1000W, PC Power & Cooling Turbo Cool 1000W, for example.)



2.The bottom line is, for 99% of the folks out there single vs. multiple +12V rails is a NON ISSUE. It's something that has been hyped up by marketing folks on BOTH SIDES of the fence. Too often we see mis-prioritized requests for PSU advice: Asking "what single +12V rail PSU should I get" when the person isn't even running SLI! Unless you're running a plethora of Peltiers in your machine, it should be a non-issue assuming that the PSU has all of the connectors your machine requires and there are no need for "splitters"

 

[Mussels]

deleted your duplicate thread. (yes, it was made twice. i assumed it was an oopsie)


while i agree that for MOST people its a non issue, there is still the issue of cheap and nasty multi rail PSU's coming with rails as weak as 16A - and that can cause issues when people pair them with high end cards. Then again, thats more about not buying a cheap PSU, than buying a single rail PSU

 

[trt740]

deleted your duplicate thread.

didn't see that I had two?

 

[trt740]

deleted your duplicate thread. (yes, it was made twice. i assumed it was an oopsie)


while i agree that for MOST people its a non issue, there is still the issue of cheap and nasty multi rail PSU's coming with rails as weak as 16A - and that can cause issues when people pair them with high end cards.

Read what he says as long as the rails are dedicated there shouldn't be any advantage. He said almost no PSU truly have more than one rail anyway even if they say they do. Hes saying that the single rail and multi rail idea is all marketing for the most part.

 

[Mussels]

my amendment to what he said isnt much of a change, but it still stands that i've personally used units supposed to have these features (one rail thats 'not really split') and it overloaded and wouldnt run certain video cards.

my OCZ gameXstream 600W for example - it would actually shut down under furmark load on my 4870 (just one) and i could see the rails voltage droop before it happened.

its an older design, and its had a few years of use - but you cant overall state that single and multi makes no difference - it just makes no difference for midrange power usage PC's and below.

if your PC uses 00W of power at load, who gives a damn. just get a reliable PSU.

More than that? well, i'd really suggest single rail just in case.



i can also state that some of his information is wrong:

So why do they do they split up +12V rails??

Safety. It's done for the same reason that there's more than one circuit breaker in your house's distribution panel. The goal is to limit the current through each wire to what that wire can carry without getting dangerously hot.

Thats not true at all. The ATX specifications had a limit in them, and PSU makes used multiple rails to get past it. Once ATX 2.03 came out, they went back to single rail since it was 'legal'

i agree with the majority of it, however.

 

[trt740]

my amendment to what he said isnt much of a change, but it still stands that i've personally used units supposed to have these features (one rail thats 'not really split') and it overloaded and wouldnt run certain video cards.

my OCZ gameXstream 600W for example - it would actually shut down under furmark load on my 4870 (just one) and i could see the rails voltage droop before it happened.

its an older design, and its had a few years of use - but you cant overall state that single and multi makes no difference - it just makes no difference for midrange power usage PC's and below.

if your PC uses 00W of power at load, who gives a damn. just get a reliable PSU.

More than that? well, i'd really suggest single rail just in case.

My 600watt Gamexstream never fails, ever!!! and I just bought a Thermaltake 850 xt but this OCZ 600 watts one is unstoppable. The only reason I bought a new PSU was the deal and my chruch needs a better PSU in the main media computer. So I will donate the OCZ to them. Here is the deal on my new PSU http://forums.techpowerup.com/showthread.php?p=1528588#post1528588

 

[Mussels]

My 600watt Gamexstream never fails, ever!!! and I just bought a Thermaltake 850 xt but this OCZ 600 watts one is unstoppable. The only reason I bought a new PSU was the deal and my chruch needs a better PSU in the main media computer

i should get luke to post a photo of his, where one of the capacitors disintegrated

mine was an overall stable unit too, but when i had the heavily OC'd Q6600 and an OC'd 4870, i could trip that one rail.

Then again, he discusses that in the article and claims its not the fault of a multi rail PSU, but just those specific designs (which i cant really fault. they dont claim what rail powers what outputs)

 

[trt740]

i should get luke to post a photo of his, where one of the capacitors disintegrated

mine was an overall stable unit too, but when i had the heavily OC'd Q6600 and an OC'd 4870, i could trip that one rail.

Then again, he discusses that in the article and claims its not the fault of a multi rail PSU, but just those specific designs (which i cant really fault. they dont claim what rail powers what outputs)

It just depends. I got a good one look what is running now and it doesn't blink.

System Name: The Big Blue Testical
Processor: Intel I7 920 4.0ghz 20x200 at 1.240v 24/7
Motherboard: ASUS Rampage Extreme II 1504 bios
Cooling: Noctua NH-U12P 120 ANTEC TRI COOLER 79CF FAN RED LED
Memory: Gskill 9GB DDR3 1600 88821 t1
Video Card: BFG 295 GTX Oced to 700/1500/2300 and it doesn't need it!!!!
Harddisk: CAVALIER SE 16MB 640GB SATA 3.0 DRIVE Segate Barracuda 80GB IDE 7200 RPM
CD/DVD Drive: 2 BLACK LG DVD BURNERS
CRT/LCD Model: BLACK LG FLATRON 23 INCH MONITOR 3000 TO 1 RATIO 1650X1080
Case:Thermaltake Armor Series VA8003BWS Black Full Tower Case w/ 25CM Fan
Sound Card: ASUS Supreme FX II HD 8.1 sound
PSU: BLACK OCZ SLI GAMESTREAM 600 WATT BLUE LED
Software: Windows Vista Ultimate 64
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[Mussels]

I just depends I got a good one look what is running now and it doesn't blink.

System Name: The Big Blue Testical
Processor: Intel I7 920 4.0ghz 20x200 at 1.240v 24/7
Motherboard: ASUS Rampage Extreme II 1504 bios
Cooling: Noctua NH-U12P 120 ANTEC TRI COOLER 79CF FAN RED LED
Memory: Gskill 9GB DDR3 1600 88821 t1
Video Card: BFG 295 GTX Oced to 700/1500/2300 and it doesn't need it!!!!
Harddisk: CAVALIER SE 16MB 640GB SATA 3.0 DRIVE Segate Barracuda 80GB IDE 7200 RPM
CD/DVD Drive: 2 BLACK LG DVD BURNERS
CRT/LCD Model: BLACK LG FLATRON 23 INCH MONITOR 3000 TO 1 RATIO 1650X1080
Case: hermaltake Armor Series VA8003BWS Black Full Tower Case w/ 25CM Fan
Sound Card: ASUS Supreme FX II HD 8.1 sound
PSU: BLACK OCZ SLI GAMESTREAM 600 WATT BLUE LED
Software: Windows Vista Ultimate 64
Reply
vBulletin Message

Cancel Changes

well, mine was an early review sample before they even hit retail its somewhat old by now.

anyway, apart from a few nitpicks i like what he wrote. there is good information in there.

 

[trt740]

well, mine was an early review sample before they even hit retail its somewhat old by now.

anyway, apart from a few nitpicks i like what he wrote. there is good information in there.

Well heck just about everything he reviews he gets to ripple but Corsair but the modular PSUs are too damn long for my case and even in quad sli with 295gtx nothing gonna stress a psu like he does. The best deal I could find was the Thermaltake modular.

 

[theorw]

What is said on the article about psus nos having actual multiple rails but rather SPLITTING power to more cables, i think is true...
I recently opened my PSU,that note has never failed me with some serious dual card OC,
and i noticed that the 12vrail cables,most of them were soldered together on the PCB and then guided to different connectors...
But i might be wrong.
I ll open it again and post some pics for all of u guy tomorrow!

 

[Mussels]

you definately do get 'multi rail' PSU's that are either single rail PSU's with a lie on the packaging (lol) or one rail split with OCP (over current protection) which shuts down the rail if too much power is drawn.

To be honest, the former is better than the latter. at least you dont get random shutdowns from improper power setups.

(as the guy said in the review, if you use a lot of power off any one rail you're in the shit - such as molex to PCI-E power adaptors, or a lot of HDDs)

 

[theorw]

So the bottom line is that for stability,factor No1 is proper split and balance of the hardware on the rails right?

 

[Mussels]

So the bottom line is that for stability,factor No1 is proper split and balance of the hardware on the rails right?

a single rail PSU, or a multi rail PSU with evenly split power will both perform admirably.


The problem comes when you have a PC which doesnt split so evenly (say, 6 HDD's and a molex to PCI-E adaptor)

 

[theorw]

a single rail PSU, or a multi rail PSU with evenly split power will both perform admirably.


The problem comes when you have a PC which doesnt split so evenly (say, 6 HDD's and a molex to PCI-E adaptor)

We both say the same thing

 

[Mussels]

indeed we do!


my concern is that people may misinterpret this and beleive that multi rail PSU's are "fine" for everyone, when we known that isnt the case (because TPU's demographic tends to rest in that 1% that does odd things with a PC)

 

[[I.R.A]_FBi]

what type of "odd things" are these?

 

[Mussels]

what type of "odd things" are these?

say, running a CPU with a massive overclock, 5 HDD's, and a gazillion high powered fans off the one rail?

fill up every PCI and PCI-E slot while you're at it with TV tuners, wireless cards, SATA RAID/E-sata cards, Physx and such... you're gunna draw a loooot more than the 'average' user off that rail that supplies your motherboard.

 

[[I.R.A]_FBi]

agreed

 

[trt740]

indeed we do!


my concern is that people may misinterpret this and beleive that multi rail PSU's are "fine" for everyone, when we known that isnt the case (because TPU's demographic tends to rest in that 1% that does odd things with a PC)

Thats true but according to Johnny unless you have 1000+ power supply, then it most likely doesn't have separate rails to begin with so it wouldn't matter. Even if it say's it does he says that they are fibbing. If overvolted they should be safer than a true single rail and shut down.

 

[Mussels]

Thats true but according to Johnny unless you have 1000+ power supply, then it most likely doesn't have separate rails to begin with so it wouldn't matter. Even if it say's it does he says that they are fibbing.

thats the part i somewhat disagree with. it may well be true in the modern, quality PSU arena - but when you start talking cheap OEM crap its a different thing.

As i said earlier - its the difference between a cheap multi rail and a quality multi rail... which is no different to single rail.

I'll write my own counter-article.

[article]
DONT BUY CHEAP PSU'S!
[/article]
(mines shorter than his )

 

[theorw]

indeed we do!


my concern is that people may misinterpret this and beleive that multi rail PSU's are "fine" for everyone, when we known that isnt the case (because TPU's demographic tends to rest in that 1% that does odd things with a PC)

Well in that case i hope they understand what they read when they do...!

[article]
DONT BUY CHEAP PSU'S!
[/article]
(mines shorter than his )