Any risk of using newer PSU on older systems? \ VOGONS

Any risk of using newer PSU on older systems?

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First post, by SETBLASTER

Posted on 2019-07-27, 17:43

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i bought a new gigabyte power supply ,650w 80plus
when i cheched the amps the 12v rail has a lot..like new PSUs
but the 5v rail is limited to 15amps

on older power supply from maybe year 2007 this was not like that ,because the 5v rail had 25amps if i remember correctly, from another brand i had back then

so are there any risks of using newer PSU on older motherboards? for esample socket 462 or Pentium4 motherboards.?

some of the socket 462 motherboards did not come with the P4 power connector and some did have it on the motherboard (does that make a difference at all?)

Reply 1 of 3, by appiah4

Posted on 2019-07-27, 18:03

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Don't use weak 5V rail PSUs with especially Slot A and Socket A boards.

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Reply 2 of 3, by SETBLASTER

Posted on 2019-07-27, 19:31

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how many amps is weak and how many amps is good?

Reply 3 of 3, by Aragorn

Posted on 2019-07-27, 20:01

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depends what your building ofcourse. A typical 200w Pentium 3 era PSU might have had 20A on the 5v rail. A 350w unit from the Athlon era might have had 30 or 35A on the 5v rail.

If the board has the seperate 4pin power, then that means its using 12v for CPU and so modern stuff is fine. P4 stuff tended to use the 4pin power, but Socket A stuff didnt until a few years down the line.

You just have to look at whats in the system and make a judgement call. An athlon 1400 is rated a bit over 70w, so on a typical 5v based board from that era, the CPU alone will be drawing the best part of 15A on the 5v rail. Then add in the rest of the system...

Similarly older GPU's tended to be powered from 5v as well.

You have to shop around a bit as well, some modern supplies do have more available on the 5v rail, but you wont typically find much more than 20 or 25A. Still not ideal, but clearly much better than 15A!

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