Mark Twain wrote:
I didn't really understand what you were asking me
although I think I understand the concept. I'm
assumed all connections are standard etc. and I
don't think they're be a problem about fitting.

Here's all the additional wiring that isn't attached to
the PSU and the power cord.

http://i66.tinypic.com/rtgojm.jpg Are these cables really long enough ?

http://i63.tinypic.com/j9o58o.jpg

http://i63.tinypic.com/f3s0g6.jpg Floppy adapter

http://i63.tinypic.com/33wqo04.jpg Molex

http://i65.tinypic.com/9vaale.jpg PCI Express with 2x3 or 2x4 option

http://i67.tinypic.com/2wem540.jpg SATA2 ?

http://i67.tinypic.com/2uha3bq.jpg SATA4 cable

http://i64.tinypic.com/359bvgw.jpg "Modular end" of cable

I did open the 780 and I test fitted the PWR1 cable
but I have no idea what the other two square connectors
go to? I looked for anything like them on the motherboard
and the HD and optical drive and couldn't find anything
close to them.

I realized later I had the PSU backwards but I don't think
it matters much.

http://i65.tinypic.com/2vsmdyo.jpg 780 custom cable outlet hole
Not same as new supply...
http://i63.tinypic.com/rk5474.jpg 2x2 and 2x4 ATX12V cable

Robert

The cables you show in rk5474 could be the two halves
of a 2x4 cable. The two pieces should "align on a small rib"
when inserted into a 2x4 connector.

http://www.playtool.com/pages/psucon...tors.html#eps8

This shows a 2x2 going into an enthusiast motherboard 2x4 connector.

http://www.playtool.com/pages/psuconnectors/4pinin8.jpg

The deal with the connectors is this:

1) Each yellow wire carries 6 amps.
2) The ATX spec defined a 2x2 connector, suited to 12A total.
12V * 12A = 144W of power. With VCore efficiency taken
into account, this can probably handle a 130W processor,
with 14W of waste heat coming from the VCore components.
3) Enthusiasts want to "overclock" their motherboards.
The power drawn through ATX12V in that case, could be
200-300W depending on situation (Pentium Dual D805 4GHz).
4) Motherboard makers started including a 2x4 on the board,
capable of carrying 288W no problem at all. There are four
yellow wires and four black wires on the 2x4.

With the accursed all-black wiring though, it's harder
to gain the visual cues, the yellow wire helping the
user align the two halves of the 2x4 to prepare them for
insertion into a 2x4 socket.

If the motherboard has a 2x4 socket

Plug in a 2x2 PSU, get up to 144W of power (non-overclocking user)
Plug in a 2x4 PSU, get up to 288W of power (overclocker user)

Your motherboards *should not* have a 2x4 on the motherboard
surface. Unless a Dell is an "Alienware" branding machine,
regular Dells are not really intended as overclocker material.

Thus, yours looks like this case.

You will be plugging at 2x2 into a 2x2 like this.
You need *one half* of your two-headed cable. The snap-tab
aligns with the tab on the motherboard.

http://www.playtool.com/pages/psuconnectors/12v4pin.jpg

Note that the connector has a cable lock. It snaps
over the tab on the motherboard. The cable lock
prevents "thermal pushout" of the connector and keeps
it seated. When removing the 2x2, you need to "depress"
the top part of the tab, to release it, while at the
same time, pulling up on the connector. On some computers,
if you have big hands, there's practically no clearance
for you to depress the tab.

The two heads, viewed end on, on the Seasonic, look like this.
You can use one head, with the tab "T" snapping onto the
mating tab on the motherboard end. The tab "T" functions
as an optical cue for orientation too. In addition, the nylon
shroud around each pin is shaped, to control insertion.
If you're having trouble fitting it, verify the "shapes"
on the section you selected, mate with the "shapes" on the
motherboard side. Two of the shroud pin enclosures are
four-sided, two are six-sided

T T TTT
X X X X == X X X X
X X X X X X X X


TTTTT End view of connector
___ ___ showing shapes which help
| | | | control mating only one way.
| | | |
\_/ ---
___ ___
| | | |
| | | |
--- \_/

If they'd stuck with the yellow wire, you would also be
able to make a note of which side was yellow when
disassembling the old PSU, and double-check yellow
was on the same side once the new connector was seated.
But with the all-black wire, one very valuable visual
cue is missing.

*******

Here is a picture of me mocking up cable insertion
on your machine with the two drive bays at the bottom
of the computer. My Seasonic cable seems to have the
correct orientation of cables, and I expect yours does too.

You can see in the picture, that really both the angled
and the straight connector on SATA4, some wire "sticks out"
between drives. Which is different than the "perfectly flat"
and nice layout, of the Dell implementation. For the
angled connectors, it depends on how much "slack" is
between connectors, as to how far it sticks out.

https://i.postimg.cc/xTBF9R0S/SATA4-fit-test.jpg

I don't think this is a big deal, but you know how
these things bolt together better than I do.

Paul