Dual 12V rails?

[HonkeyDonk]

<--- noob

So I bought a cooler master 450w PSU w/ the dual 12V and all. It has 1 4-pin square connector that I assume is a 12V connector to the mobo.

Now since this PSU is dual 12V, shouldn't there be another 4 pin square connector? Or am I really confusing/not understanding what dual 12V is?

I notice on some other PSUs, they have 2x 4-pin square connectors?

Can someone explain it to me?

thanks!
-------------------------------------------------------------------------------------
Edit: NEW QUESTION

So I have another question now...relating to the 12V rails and the Amps.

On stock speeds, I had WoW crash on me a few times. By Crash, I mean I would be playing and then all of a sudden my comp would "shutdown", my monitor enters "no signal" mode, but the fans/led lights are still running. I of course have to shut down by switching the PSU off.

I also read on DFI-street that for any DFI NF4 mobo w/ NON-SLI setup, u need at least 24A on your 12V rails.

Well I am using the cooler master 450w PSU and it has a combined 22A for the dual 12V rails. Would this be the cause of my comp crashing while playing WoW? Just off by a couple amps....

My rig:
AMD64 3000+ venice stock
DFI LanParty UT NF4 Ultra-D
OCZ Plat. Rev 2 1gb Kit
Cooler Master 450 real power PSU.

Thanks!

 

[GuitarDaddy]

The 4pin has nothing to do with dual rails. On most dual rail PS's the main motherboard connector (20 or 24pins) is on one rail, and everything else is on the other rail. A few vary from this layout, but not many.

 

[HonkeyDonk]

Originally posted by: GuitarDaddy
The 4pin has nothing to do with dual rails. On most dual rail PS's the main motherboard connector (20 or 24pins) is on one rail, and everything else is on the other rail. A few vary from this layout, but not many.

Ah i see...makes more sense that way.

So having mobo on 1 12v rail and all other on the other 12v rail allows for better power efficiency or something? more stableness I guess?

 

[birdpup]

Read Power Supply 101 for more information.

 

[Zepper]

Actually Guitar Daddy is WRONG! The P4 (CPU power) connector and perhaps the SLI connector if present are on one rail and the drive and ATX connectors are on the other. A single rail design (like the Sparkle FSP550-60PLG, some Zippys, etc.) is much more flexible than a split rail design because of the way the connectors are assigned on the split rail units.

.bh.

 

[boshuter]

The main reason you are seeing so many "dual rail" psu's is that it's cheaper to produce a psu with 2 18amp rails than it is with 1 36amp rail. The manufacturers know that if they market them as the "hot" product that all the newbs will fall all over themselves to buy one (at a higher price than a good single rail). Cheaper to make, sell for more..... you do the math.

 

[HonkeyDonk]

So I have another question now...relating to the 12V rails and the Amps.

On stock speeds, I had WoW crash on me a few times. By Crash, I mean I would be playing and then all of a sudden my comp would "shutdown", my monitor enters "no signal" mode, but the fans/led lights are still running. I of course have to shut down by switching the PSU off.

I also read on DFI-street that for any DFI NF4 mobo w/ NON-SLI setup, u need at least 24A on your 12V rails.

Well I am using the cooler master 450w PSU and it has a combined 22A for the dual 12V rails. Would this be the cause of my comp crashing while playing WoW? Just off by a couple amps....

My rig:
AMD64 3000+ venice stock
DFI LanParty UT NF4 Ultra-D
OCZ Plat. Rev 2 1gb Kit
Cooler Master 450 real power PSU.

Thanks!

 

[t3h l337 n3wb]

11A on each rail?! That's definitely not enough, especially since you have a Lanparty.

 

[HonkeyDonk]

Originally posted by: t3h l337 n3wb
11A on each rail?! That's definitely not enough, especially since you have a Lanparty.

Well actually, it's

12V1 - 18A (peak) 12A (continuous)
12V2 - 16A (peak) 10A (continous)

264W from the 12V rails. So since Power = VI, I = P/V = 264/12 = 22A

or just 10 + 12.

Isn't that how you calculate it? How do you compare single rails to dual rails in terms of amps?

1 single 12V rail @ xx amps is compared to a dual 12V rails combined amps right? So in my case it would be 22A's for the 12V rails right?

 

[Zepper]

On most PSUs all positive voltages are off a single transformer. The primary winding determines the total power capacity of the transformer. So to get peak output from the 12V rails, the others have to be more lightly loaded so that you aren't drawing more than what the primary can handle. And on most split rail PSUs, both of the 12V are off the same secondary but thru separate regulators - which sets another limit on the total output of the two rails. Everything is intertwingled...

.bh.