Re: Changing Motherboard to ASUS Z68

"Paul" <nospam@xxxxxxxxxx> wrote in message news:jgrjug$ll4$1@xxxxxxxxxxxxxxxx
Allan wrote:

Once again many many thanks for your detailed advice and help
I have a little bit or reading to do now :-)

Could you please just clarify when I might use the 6 pin ATX .................. are you saying IF the 4 pin was not powerful enough I could use the 6 pin?

Thank You

The 2x4 ATX12V (four yellow on one side, four black on the other),
is for extreme overclocking. for example, on Tomshardware, they
cranked a D 805 to 4GHz, and the power draw is over 200 watts
when you do that. A 2x2 connector would begin to overheat at that
level of abuse. And then you'd want to use a 2x4 and ensure the
12V2 rating on the power supply is 200W/12V = 17 amps or more.

In your case, you're not anywhere near that level (yet). I don't
have a 2600K here, so can't measure the power for you. I measure
the power on my processors here, by using a clamp-on ammeter to get
a DC current reading, and that's how I can tell whether I'm in
good shape or not.

To give an example, on one 65W processor, power stays below 36W,
even with Prime95. On another 65w processor, it might be around 45W.

Using an older processor (P4), the measured power was actually
a couple watts higher than the TDP value. But current generation
processors, tend to be on the low side, rather than the high side.
The high side behavior peaked around Prescott days.

Note that there are a number of small connectors on the supply.
There is the 2x2 ATX12V (two yellow, two black wires). But there
is also the 2x2 section of the 24 pin main connector, but it has
four different colored wires. Occasionally, someone tries to
connect that four different color connector, to their ATX12V, with
disastrous results.

There are also 2x3 and 2x4 PCI Express connectors, but they shouldn't
mate with the motherboard. (I haven't tested that though.)
The shapes of the nylon shell around the pins, are to help
prevent that sort of thing.

Power supplies also come with a 2x4 style connector, that splits
into two pieces. That type is handy for dealing with an old
motherboard (with 2x2 connector only on the motherboard), or
dealing with a newer motherboard with a 2x4. You split the
connector in two, when you want just a 2x2.

And some supplies, even come with one 2x2 as well as a fixed 2x4
that doesn't come apart. Usually, they'll all be part of the same
cable assembly, as a hint they're part of 12V2 output.

This page shows pictures of many of these variations.


If you're overclocking 30%, that would be 95W * 1.3 = 123.5W.
If the Vcore converter was 90% efficient, the input power needed
to provide that power level would be 123.5W/0.90 = 137.2W.

The most conservative rating for the 2x2 is 144W (12V @ 6A on two wires).
The pins might be good for eight amps each, depending on the wire
gauge used (fatter wire, removes more heat). So even at 30% overclock,
you're still under the limit. Now, if you start cranking VCore, as
the guy in that Newegg article was doing, then you might manage to
get over 144W. But without a clamp-on ammeter, it's pretty hard to

Yes, you can fit a multimeter in series with ATX12V, but your typical
garden variety multimeter has a limit of 10 amps before the fuse blows.
So to measure 12 amps, you'd need a better quality ammeter, or the
services of a clamp-on ammeter.

My ammeter can measure up to 400 amps. In fact, it doesn't really have
good "low" ranges. But being a "non-contact" device, I can quickly take
readings with it (you just clamp it around both yellow wires at the same
time, and it takes the summation of the current flow). Too bad it costs
so much more than a regular multimeter. It uses a Hall probe, to sense the
current flow. Clamp-on ammeters come in AC only, or AC/DC, and for
computer usage, you want DC measurement ranges. To measure DC
currents, implies Hall probe technology.

My clamp-on ammeter.

Using a clamp-on ammeter. When measuring an AC cord, you have to
split the wire cable between wires, so that only one wire goes
into the jaws of the instrument (otherwise, sticking the jaws around
the entire cord, the magnetic fields around the wires cancel out).
I have a home made "breakout cable" with the wires spread apart, for
that purpose, so I don't have to ruin any good cords.

On an ATX supply, all the wires are exposed, so you can get the necessary
wire groupings right within the jaws. On the output side of the ATX supply,
you're making DC range measurements. On the input side (if you wanted to do
a measurement there), it would be AC ranges. For AC inputs, a
Kill-O-Watt meter is the instrument of choice, rather than one of
these. Kill-O-Watt can take power factor into account.


So if you were doing that extreme an overclock, you'd want to
switch to a 2x4 and a newer supply with a hefty 12V2 rating.
If you're sticking to 30%, and not cranking the hell out of
Vcore, you might still be fine. I pick the 144W number to
be completely safe, but the pins probably can handle a bit
more than that.

Damage to pins, happens over a period of time. The metal on
the pin, goes from shiny to dull colored. This is oxidation
from heat, or a metallurgy change on the plating. Once
oxidation occurs, the "resistance" when the two connectors
mate goes up, which causes the connector to get hotter,
which hastens the demise of the connector. Eventually, the
connector will be a charred mess. Just as the computer
will no longer boot, you take the side panel off and there
is the connector with a pin or two completely burned off.

I've only had that happen once here. I burned a Molex 1x4
on an ATI video card. Apparently, the cheesy chinese connector
on the power supply, wasn't gripping the pin very well. (The
current flow before the incident, was only 5 amps.) Molex
have gone downhill, since every Tom Dick & Harry has been able
to make them. At one time, there were fewer sources of those
connectors, and the quality was more consistent. If you
feel a connector is not seating properly, keep an eye on it,
as it might go like mine did.

Also, the 2x2 and the 24 pin main connectors have latches.
The latch keeps the connector seated, so it can't "walk out"
and work loose. That's another way they get burned - a connector
can work itself loose, and then the pins burn. Make sure the
latch is engaged, when installing. The Molex 1x4 doesn't need
a latch, because its insertion force and retention force are
so much higher (or at least, they used to be that way).


Many thanks for that Paul .........has made things a lot clearer, and I feel happier.
Generally speaking (unless I am bored one day :-) I have no intention of overclocking, to be quite honest there is no real need for me to do that, but you know what us men are like :-)
I really do appreciate ALL your time and knowledge

Thank you


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