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New HTPC - old PSU. 20 pin plug, 24 pin socket compatibility

Posted: Tue Oct 05, 2010 1:01 pm
by ak47
Just ordered all the bits for a new i3 HTPC. As I have a relatively quiet Seasonic S12 430 watt PSU I was going to re-use it. Spent an age fixing the Big Shuriken (why do they have those twisty plugs under the heatsink with no access?!!!). Tidied the cables etc. And then came to plugging the power into the motherboard and noticed that the ATX power on my PSU is the old 20 pin plug but the motherboard has the 24 pin socket.

Can I still use this or do I need a new PSU as well now? Help !

EDIT: _If_ I was to buy a new PSU, what sort of wattage would I be looking at? Its an MSI board with a i3 540, using onboard HDMI graphics, Blackgold BGT3595 (DVB-S and DVB-T card), 2.5 500Gb HDD, Bluray drive, USB remote, USB wireless keyboard mouse.

Posted: Tue Oct 05, 2010 2:31 pm
by MikeC
Yes, you can still use it. We do in the lab all the time. The extra pins only add more paths to the same voltage lines.

Posted: Tue Oct 05, 2010 3:23 pm
by corrion
Works in reverse as well: power supplies with 24-pin cables can be plugged into motherboards with 20-pin as long as you leave the four side pins outside the plug. It'll only fit in perfectly one way, so make sure you don't jam it in!

Posted: Tue Oct 05, 2010 10:47 pm
by kater
So you're saying that S12 430 actually has a 20 pin ATX connector? Only 20 pin? I had this very PSU and mine had 24. Of course as said before, 20 will work just fine, no big deal.

Posted: Wed Oct 06, 2010 1:24 am
by ak47
Thanks all - I'll continue and hopefully finish the build soon.

The S12 I have is rather old so it has 20 pins (its not an S12II).[/url]