Motherboard power plugs

[LeadBullet]

This is just something I've been wondering about for a while.

When I put in a new motherboard (AMD) recently I noticed that it had two power plugs. The usual long rectangle one and it had another small square one with four holes in it. In the motherboard book it has a page where it labels what both of them are with how many volts they are or something.

But in the instructions it never said if I should have both connected or not. I plugged in the long one and it started up and ran fine. I plugged in the little square one as well and it started up and appeared to run fine as well. After that I shut it down and have been using it with only the big one in.

Does anyone know if I am supposed to have the little 12V one plugged in or not?

[Jeff]

What kind of motherboard is it? My Asus K8V SE Deluxe only uses the rectangular one. Never uses the 4-pin molex connector. I use that for my Radeon X800 Pro for power.

[Bludd]

It just gives you extra juice on the +12v rail. Your CPU might find it useful. It's sometimes called a P4 connector because before the P3 used the +5v rail and that changed when the P4 was introduced. I think the K7+ Athlons can use this too, so if you have the connector on the motherboard, I really see no reason not to use it.

[TerminX]

Let me put it this way: if you don't plug it in, expect either the bigger plug (known as the P1 connector) or voltage regulation circuitry on the board to burn.

[Bludd]

TerminX said:
Let me put it this way: if you don't plug it in, expect either the bigger plug (known as the P1 connector) or voltage regulation circuitry on the board to burn.



It's that serious? Interesting.

[TerminX]

Bludd said:

TerminX said:
Let me put it this way: if you don't plug it in, expect either the bigger plug (known as the P1 connector) or voltage regulation circuitry on the board to burn.



It's that serious? Interesting.


Yes, it's serious. The plug exists for a very good reason, heh.

[Tedski]

TerminX said:

Bludd said:

TerminX said:
Let me put it this way: if you don't plug it in, expect either the bigger plug (known as the P1 connector) or voltage regulation circuitry on the board to burn.



It's that serious? Interesting.


Yes, it's serious. The plug exists for a very good reason, heh.



Some boards will not run unless you have both plugged in. As outlined above, due to power requirements, that can only be a good thing. However, I'm not at all surprised that not all boards are that fussy about it, mainly due to the fact that I doubt that everyone has a psu that has both connectors, and the mobo manufacturers will likely want you to be able to run their boards without upgrading the psu. I do feel that there should be more mention of this though, whether it be on vendors sites or within the mobos manuals. When I upgraded stuff recently, I was fortunate in that my psu had both connectors, but although having researched what I was after, there was nothing to say that I really did need both plugs.

[Spyd]

I think this is a clear case of RTFM.
If the motherboard has the connector, I'm 99% secure than in the manual says you have to have it connected.
Anyway this connector will be replaced with the new ATX connector... that in fact its the same as the actual plus the four wire one attached.
The new LGA pentium boards already came with this new power connector.

[Wamplet]

In all the cases that I've seen, a mainboard that has the p4 power plug required it for the pc to even turn on. http://forums.3drealms.com/ubbthreads/images/graemlins/redface.gif

[NutWrench]

Yes. The smaller plug is a 12 volt connector than needs to be plugged in. Here's mine (Asus P4P800 Deluxe)

[Dukefan]

Wait--it's that plug? (I have the exact same mobo, NutWrench.) I thought that was only for Pentium 4's, since they have increased power requirements. There's an AMD line that uses it as well?

[Bludd]

TerminX said:

Bludd said:

TerminX said:
Let me put it this way: if you don't plug it in, expect either the bigger plug (known as the P1 connector) or voltage regulation circuitry on the board to burn.



It's that serious? Interesting.


Yes, it's serious. The plug exists for a very good reason, heh.


I just wasn't sure about the plug for AMD systems, and jeffb said he didn't have one on his AMD system.

Edit: Just to clarify, my position is that if you have this power plug you should use it. http://forums.3drealms.com/ubbthreads/images/graemlins/love.gif

[NutWrench]

I'm using a Pentium 4, so the power supply I ordered had that extra connector. If you're using an AMD processor, I supposed it possible that the power supply you ordered doesn't have that extra line.

[Bludd]

Same here. I was looking for it when I did the research into which PSU to buy.

[Crispy Critters]

jeffbthomson said:
What kind of motherboard is it? My Asus K8V SE Deluxe only uses the rectangular one. Never uses the 4-pin molex connector. I use that for my Radeon X800 Pro for power.



Jeff, your motherboard does have this. It's not a molex socket, it's a square four pin connector. On your board it's above the processor socket and just to the left.

[Bludd]

Okay, plug it in, plug it in, plug it in, plug it in, plug it in.

[LeadBullet]

Spyd said:
I think this is a clear case of RTFM.
If the motherboard has the connector, I'm 99% secure than in the manual says you have to have it connected.
Anyway this connector will be replaced with the new ATX connector... that in fact its the same as the actual plus the four wire one attached.
The new LGA pentium boards already came with this new power connector.



Well I did RTFM and it didn't clearly say what to do YF.

I just remembered though that where I plug in the big one, there were 4 extra holes but with a black cap over them. I guess that was for the new ones. The only time the book ever mentioned power plugs was saying to plug in the big one, and if it had the 4 extra slots to remove the cap and plug it in, otherwise leave it and plug in the normal one. It never once mentioned the little 12V one.

Both mine are located about around where they are on the pic just above.

[Bludd]

If you have it, plug it in.

[Wamplet]

On my AMD 3400 system, it has that plug and requires it. The plug is specifically labelled "CPU" at the base on the mainboard. http://forums.3drealms.com/ubbthreads/images/graemlins/redface.gif

[Phayzon]

my mobo has that plug but my case's power supply doesnt :P

[Bludd]

Phayzon said:
my mobo has that plug but my case's power supply doesnt :P



Get a new, high quality PSU that has, then. http://forums.3drealms.com/ubbthreads/images/graemlins/smile.gif

[Mister_Lynyrd]

my PSU has that, but the mobo in my new project computer doesn't... it's a Tyan s2266a... P4 board for my old 2.4ghz processor I'm building for my son. I just let it dangle there, uselessly, lol http://forums.3drealms.com/ubbthreads/images/graemlins/smile.gif

[Kevin Wolff]

Dukefan said:
Wait--it's that plug? (I have the exact same mobo, NutWrench.) I thought that was only for Pentium 4's, since they have increased power requirements. There's an AMD line that uses it as well?


Nice try at the slick anti-Intel jab. http://forums.3drealms.com/ubbthreads/images/graemlins/grin.gif

<table><tr><th><font size="-1">Spoiler below:</font></th></tr><tr><td class="spoiler">I don't care for an argument, this just stuck out at me.</td></tr></table>

[Dukefan]

Kevin Wolff said:

Dukefan said:
Wait--it's that plug? (I have the exact same mobo, NutWrench.) I thought that was only for Pentium 4's, since they have increased power requirements. There's an AMD line that uses it as well?


Nice try at the slick anti-Intel jab. http://forums.3drealms.com/ubbthreads/images/graemlins/grin.gif

<table><tr><th><font size="-1">Spoiler below:</font></th></tr><tr><td class="spoiler">I don't care for an argument, this just stuck out at me.</td></tr></table>



Umm, what? I'm not anti-Intel at all. I have a P4, as I said above.

[DudeMiester]

You want to talk about plugs? Look at the DFI SLI mobo, it has a regular 12 volt plug, a floppy disk plug, 24-pin main power plug, and a 4-pin power plug. The reason it has all this is to deliever the extreme amounts of power it can send to the RAM/CPU, and to power two heavily overclocked vid cards in SLI.

http://www.dfi.com.tw/Upload/Product_Picture/LP%20nF4%20%20SLI-DR.jpg

[Kevin Wolff]

What made you think AMD didn't have a high-power CPU?

[Dukefan]

Kevin Wolff said:
What made you think AMD didn't have a high-power CPU?


That's not what I said. I thought the four-prong 12V connector was introduced solely for Pentium 4's, at Intel's insistence. I didn't realize AMD also made use of them.