Machine said:
I bought a power supply with an 8 pin connector when I had a 4 pin
connector on my mobo. Of course I had to exchange the thing. I take it
this has something to do with ATX Versions? ATX version was not
mentioned on outside of mobo box.
ATX power supply specifications are here. There are a variety of
form factors, to fit larger and smaller types of computers. For
P4 and Athlon64 systems, a 2x2 connector is typical.
http://www.formfactors.org/DeveloperResources.asp
12V 12V
GND GND
EPS12V is defined here (SSI) - two rails to power two processor sockets.
Typically used on server boards, and the odd desktop/workstation board.
http://ssiforum.org/specifications.aspx#powerSupplies
12V1 12V1 12V2 12V2
GND GND GND GND
Some 2x4 equipped power supplies also use one rail, like this:
http://www.pcpowercooling.com/products/assets/TC1KW4E/mb_TC1KW4E.gif
12V1 12V1 12V1 12V1
GND GND GND GND
There are some motherboards that show the four 12V pins wired together.
A typical situation might be a single socket P4 motherboard that
has a 2x4 power connector on it. In that case, you would want
the lower version of 2x4, rather than the upper version. (Otherwise,
the 12V1 and 12V2 of the upper standard, would be shorted together.) A
good motherboard manual will show a picture of the pins and label them.
Asus terms this "EATX12V", but I think EATX refers to the 12"x13" form
factor for motherboards. I didn't think there was an EATX power
supply standard as such (I cannot find one).
(PDF page 63)
ftp://dlsvr02.asus.com/pub/ASUS/mb/socket775/P5WD2%20Premium/e2086_p5wd2premium.pdf
AMD GES specification is here (PDF page 9). You can see this standard
is quite different from EPS.
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25823.pdf
GND 12V 12V 12V
+5V PWRGOOD GND GND
There are many standards for power supplies, and it does take some
care to select the right power supply. And equipment can get
damaged, by mixing them up. Not a credit to the computing
industry, to make incompatible schemes like that.
Some EPS12V 2x4 power connectors unhook and come apart into
two 2x2 square sections. Such a power supply can be used for
either a 2x4 application or a 2x2 application.
There are also adapter cables, for taking a 2x4 that does not
unhook, and converting from 2x4 to 2x2.
*******
The above is not intended to be an exhaustive collection of
types - these are just the ones I've run into so far.
General reading:
http://en.wikipedia.org/wiki/ATX
Paul
