20 pin atx Power to a 24 pin motherboard

Stoner

Hi
I have a ASUS E35M1-1 motherboard. It has a 24 pin power connector on it but the unit is low power and will only need about 50 - 60 Watts of juice when running.

I have two PSUs both are 20 pin atx units.

They fit but i have 4 pins left over at the end, I've read that this will still work and that the 4 pins at the end are only for extra power, since this is a low power machine i was hoping that the 20 pins would be eniugh power, yet the MB was supplied with the 24 pins all the same, this may just have been to allow it to be as easy to use as possible.
http://www.smps.us/20-to-24pin-atx.html

So I'd like to know if I'll do any damage connectin the 20 pin to the 24 pin, I don't think it will but I'd like a second opinion all the same.

thanks

nb this is what I'll be doing

http://www.hardwareanalysis.com/content/image/11254/#

Leman

Really, REALLY bad idea.

There is a reason why the Mobo has 24 pins on it. Either get an old 20 Pin mobo for your setup or get a cheap low power PSU. If the system is as low powered as you say it is, it won't matter that the "400" w PSU you buy can only deliver 250w.

Serephucus

Electronically, it'll work fine. You're right; the extra four pins are just for power, so the worst that'll happen is your computer will randomly shut off and/or not boot. Did the same thing with a friend of mine and his rig a couple of weeks ago. If you get random crashes or whatever though, you know you're using too much power.

Stoner

thanks,

I checked the pin connections, i can get a jumper to feed the extra pins if needed. I don't want the losses or the fan of a 400W PSU , the PSU I have has two spare flat connections, and I had an adapter before the plugged into one of them and converted into the 2x2 plug top (2x12V) it powered a graphics card and it worked fine. So I'll try dig out a couple of the connectors, I checked the pins on the Motherboard and the voltages will line up correctly so all will be good. Thanks lads.

cyburger

You can get 20 to 24 pin adapter cables like this one?

http://www.scan.co.uk/products/akasa-24-pin-(m)-to-20plus4-pin-(f)-extension-cable-(30cm)-(end-to-end)-ak-cb24-24-ext

Serephucus

All they do is pull power from the other 20 pins. They're actually a worse idea, as they could overload your PSU.

Stoner

Ok, I just ended up making one. The one 12V pin supply is crimped, connected and linked around where it needs to go, I just brought com and 5V to the SATA, the 2 x 12V connection to the MB is shared with the 12V connection on the MB.

I have Zero problems, all the leads on the internet I have seen for these types of builds do the same, many link out the pins on the connector side, I did not, I used all the connections I could to reduce the over all resistance, I also kept the cable lengths to a minimum, but will go again on some of them.

Electrically the circuits on the DC DC units I've examined all only have one 12V, one 3.3V , one 5V and sometimes one 24V section on the DC DC unit, so it all goes back there anyway. The DC DC unit is rated at 120W and the PSU I have feeding it is 60W.

I carried out the connections and kept linking to a minimum, I did not connect cables that were not needed, the connections are sound and the cable lengths are as short as possible.
That's all i could do really.

Notes this is for a low power build, not a gaming rig, the PSU has been effectively split between the AC/DC supply and the DC DC regulator, other larger PSUs may have more going on in the regulator and have electronics behind the extra 4 pins on the 24 pin uint, these small units dont but I would not link the cables out for a larger build.

thanks again everyone.

It's all working now, using it as we speak. thank you for all the advice