20pin/24pin main connector

mikkey

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May 28, 2005
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18,510
Can you use a 20pin psu in a 24pin mobo, I read the forum post below:
http://forums.anandtech.com/message...7&enterthread=y
and they say you can use a 20pin in a 24pin mobo. They say the extra 4 pins are for pci-e and if your pci-e card has an external power outage (6pin) then it will work fine.

I just wondered if this is true and the views of some of the experienced people here. I have just purchased a Epox nforce 4 pci-e motherboard and a x850xt pci-e and wondered if my current psu will work with the board (I dont wanna blow it up).

The mobo book says you need to use the 24pin socket and the 4pin socket next to it simultaneously. My current PSU im guessin is a atx 1.3 ( or whatever there called) and has a 20pin with a 4pin square molex and the usual 4pin long molexs for hdd etc. My x850xt came with a converter from 2 long 4pin molexes to a 6pin pci-e to power the card.

So the questions are:

Is it safe to use a 20pin in a 24pin slot?
Also if so do you plug in the 20pin and the square 4pin molex?
 

Crashman

Polypheme
Former Staff
You won't blow it up. The connector only fits in one way, with the 4 empty pins to one side (it won't fit in with the 4 empty pins on the other side).

Most 24-pin boards will run on a 20-pin supply, but a few have stability issues when doing so. I'd try it because even if it crashes, the parts won't get hurt. And you might just find it runs good.

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mikkey

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May 28, 2005
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thank you for your reply. The psu I have with 20pins is a 550w, are the 4 empty pins for pci-express?

Also in the epox manual it says the main 24pin and a 4square pin should be plugged in simultaneously, this meaning I must have them both plugged into the board?

I have ordered a new 485w atx 2.0 24pin/6pin pci-e psu but it wont be here for another 4 days and I wanna try out my new hardware :D (impatient)

<P ID="edit"><FONT SIZE=-1><EM>Edited by mikkey on 05/28/05 07:36 AM.</EM></FONT></P>
 

Crashman

Polypheme
Former Staff
The four-pin square plug is for CPU power. The extra 4 pins on the 24 pin are supplemental to the 20-pins already there, they serve the same function but add input capacity (current carrying capability).

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<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>