20-pin ATX power connector vs 24-pin mobo

[wpcoe]

I've been sorting through my collection of computer debris from past builds, seeing what I can resurrect and what I should discard.

One mis-match I have is a Asus P5LD2 mobo with (what I think is) a P4 D830 processor. The motherboard has a 24-pin ATX power socket, but the only spare power supply I have is a Trendsonic 500W labeled "Pentium 4/Athlon," but no model number, which only has a 20-pin ATX power connector.

Would the mobo boot up on a 20-pin connection? Would there be a risk of damage?

If I did destroy both the mobo/CPU and PSU, it'd be no great loss, but I thought I'd check first.

I recall reading that mobos that have an 8-pin ATX/12V connector can run with just a 4-pin connection if there is not a heavy current draw. Would it be similar for the main 20/24-pin ATX connector?

[Face2Face]

Here you go.

http://www.smps.us/20-to-24pin-atx.html

and here

http://www.youtube.com/watch?v=GIZvHz5tKWY

[dawp]

yes, you can use a 20 pin power connector on a 24 pin motherboard. it should work fine without that adapter that face to face linked to. just make sure it has the 4 pin square plug for additional juice for the cpu.

[Deders]

I believe the extra 4 pins on the 24 pin plug is for supplying extra 12v power to the PCIe slots as they are supposed to be able to supply up to 75w from each slot.

You should be fine if you are using on board graphics or a very low powered (~30w) card if there is an extra molex socket on the board itself.

[Avalon]

Yep should be fine. I used a 500w PSU with a 20pin and 4pin on a board with a low power CPU and no graphics that had 24pin and 8pin connectors. Worked fine.

[Insert_Nickname]

Originally Posted by Deders

I believe the extra 4 pins on the 24 pin plug is for supplying extra 12v power to the PCIe slots as they are supposed to be able to supply up to 75w from each slot.

Just mind the 12v rail. Many older PSU's are built with relative weaker 12v rails then today, as older boards draw most power from the 3.3v and 5v rails. If the 12v rail on the PSU can do above 15A, you'll be fine if its a quality unit.

[Deders]

Originally Posted by Insert_Nickname

Just mind the 12v rail. Many older PSU's are built with relative weaker 12v rails then today, as older boards draw most power from the 3.3v and 5v rails. If the 12v rail on the PSU can do above 15A, you'll be fine if its a quality unit.

This is true but the danger in this case is if the wiring or circuitry isn't thick enough or designed to handle higher amperages.

[Insert_Nickname]

Originally Posted by Deders

This is true but the danger in this case is if the wiring or circuitry isn't thick enough or designed to handle higher amperages.

Hence why I wrote that if the PSU is rated for 15A+ on the 12v rail, I'll have to assume the wiring/circuitry is good enough that it can handle that...

(assuming a straight 12v that's still ~180W of power, enough for even the most power-hungry P4)

[wpcoe]

I've had a fun (and nostalgic) couple days tinkering with four old computers, one of which is the Asus P5LD2 with the Intel D-830 CPU. Emboldened by the posts in this threads (thanks!), I went ahead and tried it, but an ATI X1300 video card wouldn't function with just the 20-pin power.

Turns out, I had a 24-pin (20+4) ATX power supply in an even older Pentium 4 system, and it only used 20 pins, so I swapped the PSUs. Problem solved. With the 24-pin PSU, the X1300 video card fired right up on the P5LD2 mobo, and the old P4 system is just as happy with the 20-pin PSU.

Thanks for the replies. They were persuasive enough for me to soldier on.

Now, what to do with 3.0Ghz Pentium 4 and 3.0Ghz Pentium D-830 computers? I also have C2D e6750 and i5-760 systems. The former will go to my mother next month, and I'm debating what to do with the i5-760. I wish there were an active eBay-type system here in Thailand to sell things.