power connectors on motherboards...


G

GT

New motherboards seem to use 8-pin extra power connectors for the extra CPU
power. My current Core 2 board has a 4 pin 12v socket for extra CPU power.
My power supply has a 4 pin 12v extra connector to match. If I change my
current 775 board to a newer 775 board with an 8 pin socket (plus more
memory support etc), what options do I have...

1. Use the 4 pin plug in half of the 8 pin connector socket.
2. Buy a converter cable
3. Buy a new PSU

??
Thanks,
GT
 
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G

GT

GT said:
New motherboards seem to use 8-pin extra power connectors for the extra
CPU power. My current Core 2 board has a 4 pin 12v socket for extra CPU
power. My power supply has a 4 pin 12v extra connector to match. If I
change my current 775 board to a newer 775 board with an 8 pin socket
(plus more memory support etc), what options do I have...

1. Use the 4 pin plug in half of the 8 pin connector socket.
2. Buy a converter cable
3. Buy a new PSU

Incidentally, some new PSUs (even high powered units) come with 4-pin 12v
CPU power connectors also!
 
P

Paul

GT said:
Incidentally, some new PSUs (even high powered units) come with 4-pin 12v
CPU power connectors also!

You can use a four pin (2x2) power supply on a 2x4
desktop single socket motherboard. The 2x2 cabling is
good for a processor of up to 130W or so. If you're
doing a fiendish overclocking experiment, like
running a D 805 at 4GHz (which draws 200W+), then
at that point, the motherboard should have a 2x4 power
connector (and a large number of phases on the Vcore
circuit).

It would be nice if the latch on the 2x2, still hooked
into the latch on the 2x4 motherboard. That helps to
reduce the risk of the power connector "walking out" of
its mate. That happens due to thermal expansion. So
I'd prefer if the plastic latch still worked.

If you have a dual socket motherboard, such as a server
board, in that case the 2x4 may actually be wired as
a couple of independent 2x2 connectors (one per processor).
In that case, the motherboard will have a name specified
for the power supply, hinting at the different wiring
pattern of the 2x4. Then, you actually need the 2x4 type
power supply, as both a 12V1 and 12V2 will be used on the
connector. But if the motherboard is a single socket desktop
board, you don't have much to worry about. In that case,
the 2x4 has redundant pins, and the 2x2 will supply it
just fine.

Desktop connector pinout - a 2x2 works in this 2x4.

12V1 12V1 12V1 12V1
GND GND GND GND

Server connector pinout - a proper 2x4 is needed in this case.
Especially if you want to use the second processor socket.

12V1 12V1 12V2 12V2
GND GND GND GND

There is no need for adapters at this point. Verify
that the power supply provides the number of watts
needed for the new build.

Paul
 
G

GT

Paul said:
You can use a four pin (2x2) power supply on a 2x4
desktop single socket motherboard. The 2x2 cabling is
good for a processor of up to 130W or so. If you're
doing a fiendish overclocking experiment, like
running a D 805 at 4GHz (which draws 200W+), then
at that point, the motherboard should have a 2x4 power
connector (and a large number of phases on the Vcore
circuit).

It would be nice if the latch on the 2x2, still hooked
into the latch on the 2x4 motherboard. That helps to
reduce the risk of the power connector "walking out" of
its mate. That happens due to thermal expansion. So
I'd prefer if the plastic latch still worked.

Perfect info - thanks. I have a Core 2 65w and no intention of overclocking
(undervolting if anything perhaps), so it sounds like I could upgrade my
board to one with more useful features and more memory slots and not worry
about it having an 8 pin (2x4) extra CPU power connector and I can keep my
existing power supply with its 4-pin (2x2) plug.

Given that my CPU is 65w, do I even need to bother with the 2x2 pin power
connection?

Marvelous!
 
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P

Paul

GT said:
Perfect info - thanks. I have a Core 2 65w and no intention of overclocking
(undervolting if anything perhaps), so it sounds like I could upgrade my
board to one with more useful features and more memory slots and not worry
about it having an 8 pin (2x4) extra CPU power connector and I can keep my
existing power supply with its 4-pin (2x2) plug.

Given that my CPU is 65w, do I even need to bother with the 2x2 pin power
connection?

Marvelous!

The Vcore regulator has to get power from somewhere :)
So you'll need at least the 2x2 to achieve that.

Paul
 

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