20 pin psu with 24 pin mobo

guggas

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I'm trying to help a friend upgrade his older pc on a very tight budget. He has bought a new motherboard and cpu and ram. Is it true that he can use his old 20 pin psu on the new 24 pin mobo, as long as he is using integrated video? I have read that the only reason the extra 4 pins are there is to run the PCIe slot, is that true and we can run the pc with the old psu assuming the psu puts out enough amps/wattage overall ?

thanks.
 

mister g

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That depends on how old the PSU is, tell me more about your PC. Sometimes PSUs based on their age might not output the correct voltage to modern hardware and damage them. However I have seen a 20-pin in a 24-pin mobo working fine. So I would agree with you for now but list your PC specs anyway.
 
A very old PSU could have other serious issues however.
Firstly, it might be very light on the 12V power a modern system needs. Many years ago PCs needed more 3.3V and 5V power, and the balance was different in PSUs as a result.
Secondly, any PSU that has been used extensively can wear out, providing unstable power and damaging the components it is trying to power.
 
And the contrarian rides again. :D

As long as the PSU can output the needed power, the OP will be OK. An adapter is useless.

20 pin --> 24 pin adapter.
History lesson:
Long ago, they had 20 pin PSU connectors and everything was powered from the motherboard. Components became more power hungry.

PSU connectors went to 24 pins. The four extra pins were one each 3.3, 5, and 12 volts and a ground. CPU's got their own 12 volt connector and 5 and 12 volt power through the main power plug dropped.

Video cards got bigger and got their own 12 volt power connectors and 5 volt power through the main power plug dropped.

RAM went from SDRAM (3.3 volts) to DDR2 and DDR3 (1.65 - 2.2 volts) and 3.3 volt power through the main power plug dropped.

You don't need an adapter.
 
Shadow, can't explain that. All I can say is that the adapter will not improve the amount of power that the PSU can deliver to the system.

That was apparently one of the those "YMMV" times.

A couple of years ago, one of my household systems died. I rebuilt it with a modern Gigabyte motherboard. I reused the 7 year old, 20 pin Antec 400 watt PSU. Ran flawlessly.

That was apparently on of the those "YMMV" times.
 

guggas

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heres the info i was able to get from my friend.

"i think the brand is worldwide marketing limited model no iso258 input 115v/230 v."

I've never really heard of that brand.