Dual +12V Rails > This is linked from the PS Guide <

[davidhammock200]

> Linked to PS Guide <

Dual +12V Rails: Most PS’s today supply all of their +12V amperage through one rail, just like almost every PS manufacturer supplies their +3.3V and +5V through one rail each. However some forward thinking manufacture’s are supplying their +12V amperage through more than one rail, the most common today for PC’s is to use two +12V rails or dual rails.

Let’s look at these two excellent OCZ PS’s, where we see that the older design 520W puts out a very respectful 33A on one rail, while the new 600W offers a total of 38A on two rails, and try to answer the following questions:

$148.00 & $6.99 shipping > NEW HIGHER PRICE $159.99 & $6.99 shipping
OCZ PowerStream 520W Power Supply With Adjustable Power Rails With LED Indicators, SATA Connector, Model "OCZ520ADJ" -RETAIL
Model# OCZ520ADJ Item # N82E16817104152
Output: +3.3V@28A, +5V@40A, +12V@33A, -5V@0.5A, -12V@0.5A, +5VSB@2.0A
http://www.newegg.com/app/ViewProduc...104-152&depa=0

$190.00 + S&H
OCZ PowerStream 600W NEW
Power Supply With Adjustable Power Rails With LED Indicators, SATA Connector,
Output: +3.3V@28A, +5V@46A, +12V1@20A, +12V2@18A, -5V@0.5A, -12V@0.5A, +5VSB@2.0A
http://www.monarchcomputer.com/Merch...gory_Code=NA_1

Why more than one +12V rail? Electrical isolation for noise and improved voltage regulation. Some devices, usually electromechanical ones having motors, produce noise spikes & voltage fluxuations, these can include pumps, compressors, fans, drives, lights (when turned on & off) and probably TEC’s & Peltiers. By putting these “noisy” devices, that often turn on & off, or at least often change their power (amperage) demands, on a separate rail we isolate them from the MoBo, CPU, Video Card(s) and the other electronic components that are sensitive to noise & sudden changes in voltage. This is a good thing!

Are 2 rails better than 1? Short answer = Yes. It depends on your system as to weather or not dual rails would actually be of any benefit. If yours is a simple system, with no exotic cooling, large disk arrays or flashing lights, then you would probably not benefit from dual rails.

Do I need 2 or more +12V rails? Short answer = No. It depends on your system as to weather or not dual rails would actually be of any benefit. If yours is a complex system, with exotic cooling, large disk arrays or flashing lights, then you would probably benefit from dual rails.

What is the difference between dual rails and just using a splitter? In a dual rail design the PS has two transformer taps and control circuitry for two separate +12V rails. Using a splitter can be very helpful, especially if you split off your “noisy” loads very close to the PS, as this will lessen their effects on your more sensitive components, however the dual rail design would still be much better if you have a lot of “noisy” loads.

Why do all of the newer PS’s from the big names have so much +12V amperage? The future is going to be much hotter! And I’m not talking about Global Warming, or at least not directly. Back in the P3 & before days, the +12V rail did not have all that many demands placed on it. Today, it is very stressed with lots of demands & in the future, at least until we go to +20V rails (or whatever voltage they finally decide upon), it will be even more stressed with more demands. With the Thermalright XP-90 we have just about reached the upper limits of normal air-cooling. Apple has already gone beyond air-cooling and historically Apple has often lead the way for the PC world. Overclocked Intel P4 Prescott’s can only be kept at reasonable temps with extreme effort. Both AMD & Intel are soon to bring to market “Dual Core” CPU’s, which will require more power to operate and cool than a similar design single core CPU. In the future for “High-End” and “Overclocked” systems we are going to need all of the +12V amperage we can get and it should be on more than one rail for “Electrical isolation for noise and improved voltage regulation.”

The future of ATX PS's is dual rails, as the "ATX 12 v2.0" spec requires them.

I hope that this has been of help. Please post your questions, experiences, comments & recommendations.
They are always greatly appreciated!

Thank you,
Dave

> Linked to PS Guide <

[83tc]

great write up. maybe i'll save for the 600w afterall.

[Jafar]

a total of 51 amps on the 12v rail is just insane!

my ocz powerstream 470 with 33 amps on the 12V rail is awesome!

[davidhammock200]

Originally Posted by 83tc

great write up. maybe i'll save for the 600w afterall.

PC P&C's newest ones are going to be 650W+ & 850W+ !!!

EDIT:

The new OCZ 600W has a total of 38A on its 2 +12V rails.

+12V1@20A & +12V2@18A

Sorry for the mistake, I was looking at another PS, those "might be" the +12V rails of a new PC P&C PS.

[TheCleaner]

the world is going power mad.. fossil fuel running out, while new machines buolt that take more than double the power of mahines a few years ago.. although its safe to say productivity/performance for that extra power is rational

51A on a 600W psu.. WOW, my antec tp 550w.. at a time, one of the best money could bu.. new looks rather weak with only 24a on the 12v rail

[davidhammock200]

Originally Posted by TheCleaner

the world is going power mad.. fossil fuel running out, while new machines buolt that take more than double the power of mahines a few years ago.. although its safe to say productivity/performance for that extra power is rational

51A on a 600W psu.. WOW, my antec tp 550w.. at a time, one of the best money could bu.. new looks rather weak with only 24a on the 12v rail

When are you going to post a section on reading (NOT TRYING TO READ) amperage?

EDIT:

The new OCZ 600W has a total of 38A on its 2 +12V rails.

+12V1@20A & +12V2@18A

Sorry for the mistake, I was looking at another PS, those "might be" the +12V rails of a new PC P&C PS.

[83tc]

what in the world would u use 850w for!? u could run 2 off 1 PSU i guess (dumb idea i'm sure). i might be in the marke for a new PSU sooner then i'd like. my main rig just went down . everything froze after being stable at the same setting for several weeks 24/7. after i shut it down it wont start again. i get lights, power for a second then nothing.

[davidhammock200]

Originally Posted by 83tc

what in the world would u use 850w for!? u could run 2 off 1 PSU i guess (dumb idea i'm sure). i might be in the marke for a new PSU sooner then i'd like. my main rig just went down . everything froze after being stable at the same setting for several weeks 24/7. after i shut it down it wont start again. i get lights, power for a second then nothing.

Well, if you had a dual Opteron workstation with 2 dual core Opterons and a 6-Disk RAID 0+1 array in addition to your boot & page/swap file disk...

Or maybe a 4 CPU server with about a dozen HDD's in dual SCSI Ultra 360 RAID 5 arrays...

Could be an Exteeme Overclocker with quad cooling going for Win stable 5GHz with AMD's next gen A64's...

[Victim]

Thanks DavidHammock200 , you sure have this PSU thing nailed down. Top effort, much appreciated.

[davidhammock200]

Originally Posted by Victim

Thanks DavidHammock200 , you sure have this PSU thing nailed down. Top effort, much appreciated.

Your Welcome & Thanks!

[cricketman]

i don't understand quite about the dual/single rail PSU. i'm about buying a new Enermax PSU. i saw the new with dual 12v rail

EG485P-VHB SFMA
Output: +3.3V@30A;+5V@32A;+12V1@16A; +12V2@15A

EG465P-VE FMA
+3.3V@35A, +5V@35A, +12V @33A

my system has some case fans that's all. in this case what PSU should i buy ? i need a strong 12v rail for the CPU. i'm using the NF7-s right now, but i'll upgrade to the 939pin mobo very soon. i don't want the 12v rail when the CPU full load 12@11.8x or 12@11.90.

the dual 12v rail i can use either v1 or v2 ? can i use 2 at the same time ? if it's not allowed me to use 2 rails at the same time then the dual seems not too good for me, coz v1@16A or v2@15A

thanks all

[davidhammock200]

Originally Posted by cricketman

i don't understand quite about the dual/single rail PSU. i'm about buying a new Enermax PSU. i saw the new with dual 12v rail

EG485P-VHB SFMA
Output: +3.3V@30A;+5V@32A;+12V1@16A; +12V2@15A

EG465P-VE FMA
+3.3V@35A, +5V@35A, +12V @33A

my system has some case fans that's all. in this case what PSU should i buy ? i need a strong 12v rail for the CPU. i'm using the NF7-s right now, but i'll upgrade to the 939pin mobo very soon. i don't want the 12v rail when the CPU full load 12@11.8x or 12@11.90.

the dual 12v rail i can use either v1 or v2 ? can i use 2 at the same time ? if it's not allowed me to use 2 rails at the same time then the dual seems not too good for me, coz v1@16A or v2@15A

thanks all

Dual (or more) rail is the future & for good reason as it isolates the noisy motors on one rail, while the other rail supplies the MoBo, CPU, Video, etc. with very clean, stable power.

[trip]

Ok, I'm a OC wanab and considering my PSU options. If dual 12v rails are the future, then how many amps are enough on the motherboard/cpu rail? My budget is low, but understand the importance of the PSU. I have found the Enermax EG425P-VE-SFMA at zipzoomfly for $69 shipped, which has dual 12v rails (15a & 14a). Is this enough to OC? I'm in the process of reviewing and putting together my hardware and my shortlist looks like this:

abit ic7-g
p4 3e
geil 1gb pc-4000

[davidhammock200]

Originally Posted by trip

Ok, I'm a OC wanab and considering my PSU options. If dual 12v rails are the future, then how many amps are enough on the motherboard/cpu rail? My budget is low, but understand the importance of the PSU. I have found the Enermax EG425P-VE-SFMA at zipzoomfly for $69 shipped, which has dual 12v rails (15a & 14a). Is this enough to OC? I'm in the process of reviewing and putting together my hardware and my shortlist looks like this:

abit ic7-g
p4 3e
geil 1gb pc-4000

Get it, that sounds like a good deal to me!

Enermax makes very good PS's & thoses rails should be fine for a single CPU PC.

[Ket]

Originally Posted by 83tc

what in the world would u use 850w for!? u could run 2 off 1 PSU i guess (dumb idea i'm sure). i might be in the marke for a new PSU sooner then i'd like. my main rig just went down . everything froze after being stable at the same setting for several weeks 24/7. after i shut it down it wont start again. i get lights, power for a second then nothing.

might be a short, unplug power and press power button a few times then plug mains back in and see if it works.