Why would i need dual 12v?

[brad-]

whats the deal with dual 12v psu?

then hammer the noobie for asking the stupid question

 

[BillR]

A lot of the new motherboards and processors place a much higher demand on the 12-volt side of things these days. The current spec calls for dual 12-volt rails to help balance the load. Some really heavy-duty systems even require 3 rails or multiple PSU’s to keep pace with the demand.

Make sense?

 

[brad-]

what the f?

can you specifically tell me in my case if i NEED it? im just about to order all my stuff. Here's some of my core components.

AMD Athlon 64 3200+ Winchester(939)
$190
http://www2.newegg.com/Product/Product.asp?item=0-N82E16819103502

MSI RX800XL-VT2D256E Radeon X800XL 256MB 256-bit GDDR3 VIVO PCI-Express x16 Video Card
$319
http://www2.newegg.com/Product/Product.asp?item=0-N82E16814127156

ASUS A8N-SLI Socket 939 NVIDIA nForce4 SLI ATX
$160
http://www2.newegg.com/Product/Product.asp?item=0-N82E16813131524

 

[Autochthon]

BTW I found a 300 watt +/-25 A remorely switched power supply over on some mod sight but they wanted almost $100 for it. I'm better off buying a new PSU and modding it

 

[Ice Czar]

a quick cut and paste
original question regarded upgrade paths
addresses split rails and why when answering that question like many other the correct answer is....it depends
its not solely your config but other power supplies
-----------------------------------------------------------------------------------------------------------------------------

the ATX 2.2 mobo spec urgently recommends any PCI-E mobo employ the new 24 pin standard, so definately get a natively 24 pin supply, getting a supply that also has a ton of +12V amps is important for an infrastructure investment, PCI-E's spec just doubled from 75W (6.25A +12V ) to 150Watts (12.5A +12V) now those cards arent out, and even when they are that doesnt mean they will actually employ all that current, but the historical trend hasnt exactly been down

so as far as upgrade paths its really a question of how far you want to go
as mentioned dual cores arent adding alot, a drive will need 2A as an average, but only at spinup, at which time your not pegging the CPU or GPU, under normal operation post spinup it needs approx 0.5A +12V (varies a little with seeks and the arm moving) again not a great concern with just a few drives, but adds up with any large array. (I run a 6 drive RAID)

what youd be hard pressed to get right now is a supply that would do dual core, dual PCI-E 150W cards and alot of drives (about the only supplies out there would be the 700W Zippy and PCP&C 850ETX), but provided its lean on drives dual core + dual PCI-E 150W is likely doeable with many of the modern 600Watt supplies like the Seasonic S-12, Enermax SLi, PCP&C 510 SLI (650W), ect

for a single PCI-E 75W w\ dual core alot more PSUs are available
even older ATX12V v1.3 hybrid supplies like The bigger Powerstreams will do
and many would likely be relavent even with an eventual upgrade to PCI-E 150W

for quite and efficient with lots of +12V amps the S-12 600W is hard to beat
there is an SLi varient of it as well




as a note, I think its very likely the ATX12V mobo spec will change with the release of PCI-E 150W and add 4 more pin to the 4 pin +12V auxillary mobo connect, making it an 8 pin like you see on an EPS12V supply, in fact I thingk the 2 specs will merge at that point
(to EPS12V common plane, not split plane) so a supply that is an all in one, being both ATX12V v2.01 and EPS12V compatible would be an advantage
(the 24 pin connector and split rails was adopted by ATX12V \ formfactor.org, from the EPS12V SSI (server system infrastructure) spec, Intel drives both bodies, and merging the specs looks more and more likely to at least some degree)

the advantage of split rails is the isolation of variable loads being drawn form competing devices, enhancing rail stability in supplies with just basic load regulation schemes, in supplies with superior load regulation this isnt nearly as important, and since all the amps are on a single rail its more flexible, with all the amps available.
the mark of a truely compliant ATX12V v2.0 supply isnt the connector but rather the dual rails, (an EPS12V would have 3 or 4) there are many supplies that are compatible across specs, but not compliant

So compliance isnt a defacto indicator
The PCP&C in my sig is an example of that, its an EPS12V compatible, but ATX12V v1.3 compliant supply (single +12V rail regulated to 1%)
that outperforms all but a few EPS12V compliant supplies (Like the PCP&C 850ETX )

The King of the upgrade path costs a small fortune and is that PCP&C 850ETX it has a whopping 60A +12V (rated at 50C) across 4x +12V rails (split plane, each CPU get its own) and is designed specifically for dual cpu dualcores with dual SLi PCI-E 150W cards and a large RAID array thrown in
in otherwords a modern kickas workstation that would put many a current quad to shame

 

[brad-]

thanks. theres some info i can use.

 

[Dan_D]

Well my Antec NeoPower 480 was giving me massive voltage drops under certain situations with my PC and I upgraded to an Enermax Noisetaker 600Watt and so far I am very pleased.