DMP said:
My thanks to you Paul & Frank for your answers.
I have given my husband the info you both provided. He is an electronics
hobbyist and said he believes he could construct an adapter with little or
no difficulty.
I looked at the 6 pin pci-e connectors and they are not the same physical
connector as our 6pin auxiliary; the voltages are not the same either.
We will read the links in both of your messages and then take some course of
action.
Take a look at this link....will the second adapter on the page do the trick
or is this one of the things Paul refers to as a "feel good" exercise rather
then a problem's solution?
http://www.power-on.com/connectors-adapters.html
The folks here in this group helped me a great deal when we updated my PC
with a new mobo/CPU/Memory a few months ago. I never knew of Memtest or
heard of it, because there was no need, but it saved me from going insane.
It was because someone here was kind enough to help me. I was/am very
grateful for the help I received. The spouse did all the hardware...he got
off easy. I suffered with flashing BIOS's, motherboard drivers, memory
errors and changing configurations in the BIOS and a couple of chats with
M$oft about the number of my installs.
But, in any event, thanks to all for helping. Now we are about to
cannibalize an old PC to use as a backup.
Diane
The second one down is labeled ATX to ATX12V. It seems to be doing
more than that.
http://www.power-on.com/images/product/accessories/atxtoatx12v.jpg
20 pin <-------+-----+------> 20 pin
PSU | |
| +------> 1x6 Aux
|
+------------> ATX12V 2x2
Start with an analysis of current flow. The purpose of the 1x6, is to use
more pins to carry 3.3V and 5V currents. Now, what is happening on the
source side - the 20 pin connector on the left ? All the current flows
through the same number of pins there as before. That means the connector on the
left gets hot and the plastic melts, while the connectors on the right are
still within temperature limits. This is an example of an assembly that doesn't
solve any problems. If the motherboard on the right, was really drawing a lot
of current, then where the adapter meets the ATX PSU (i.e. the leftmost
connector in the picture), there could be damage.
If the motherboard is not drawing "to the max" (and yours is likely not doing
that), that Power-On.com cable assembly does help spread out current flow.
Say, for example, there was a thin connection between the motherboard 1x6
connector, and the main 20 pin connector on the motherboard (copper traces
between connectors). That makes it difficult for current flow to equalize.
The above cable assembly could help, if the motherboard was poorly designed.
I suspect the P4T-E is a 6 layer design (most motherboards are four layer),
and six layers is used to do stripline routing for RAMBUS. Which means there
is likely plenty of copper for current equalization purposes.
Your hobbyist husband, would do the following if adding a cable. In this case,
the current flow on the 1x6, takes a separate path. ~70% of the load flows through
the upper cable, and ~30% through the lower cable (just rough numbers
for illustration purposes). Nothing gets stressed more than it was stressed
before. The only downside to this, is entering the power supply, and having
to find a soldering iron big enough to heat up where the loom meets the
distribution board.
20 wires --------------------> 20 pin (on mobo)
6 wires --------------------> 1x6 Aux on mobo
inside the
supply
Now, on to a couple pet peeves. Below is the Power-on.com 20 to 24 pin.
Again, the right hand side is using more pins, so the current is spread
out more. But if a motherboard had two PCI Express video cards in SLI or
Crossfire, the single 12V pin on the 20 pin on the left, ends up carrying
a maximum load of 8 amps. This cable assembly looks pretty, but is deceiving
you. The left hand side could melt or the metal on the pin could oxidize
from the heat. At least the motherboard would not get damaged, but the
connector on the PSU could be ruined.
20 pin <--------------------> 24 pin
PSU motherboard
This following one is simply not using four of the pins. You use this cable,
only if there is an obstruction around the 20 pin motherboard connector, that
prevents the 24 pin from being connected directly. You can actually connect
a 24 pin ATX main connector, to a 20 pin motherboard. Pin 1 goes to Pin 1, and
four pins hang over one end. Sometimes, a capacitor is right next to the
connector, and if that is the case, then you buy one of these. There
are no deceptions on current here, and no additional danger of burning or
overheat. It looks pretty, and is only necessary in a few cases.
24 pin <--------------------> 20 pin
PSU motherboard
Finally, their dual 1x4 Molex to PCI Express 2x3 power adapter.
http://www.power-on.com/images/product/accessories/drivetopciexpress.jpg
That one isn't bad, as these things go. The PCI Express end is supposed to
have three 12V pins (yellow wires) and three GND pins (black wires). By using
two Molex connectors, they managed to bring across two yellow wires. That
means one of the 12V pins will be missing. They did get a total of three black
wires, so all the GND pins are accounted for. In other words, the adapter
is good for 2/3rds of whatever its "normal maximum" would be. Now, in the
case of PCI Express design, the connector is overengineered. I think industry
practice is, to never run more than 75W through the 2x3 connector. 75W / 12V
is about 6 amps. That is about 2 amps per pin. The pins are good for slightly
more than 6 amps a piece. So using two pins, and running 3 amps through each
pin, is not really testing the limitations of the pin.
I don't like to see the "single Molex to PCI Express 2x3" version, as that
one is ultra-cheap, and is relying on good current distribution on the
video card. If the video card designer cuts corners in the current
distribution near the power connector, then some heating could occur.
The version of adapter shown above (2 pins for +12V), would be in my
"acceptable" catagory, in that I don't see a long term problem from using it.
Nobody makes a "proper adapter", so in fact the example above is about as
good as those adapters get. The only way to do better, is make your own
And I don't see a reason for doing so.
In terms of your 1x6 problem, either don't connect it, or have your
hobbyist husband fit a cable assembly into the supply.
HTH,
Paul
