How much on the 5v rail? \ VOGONS

How much on the 5v rail?

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First post, by Shadobi

Posted on 2025-07-24, 23:04

Shadobi Offline

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Joined: 2025-07-07, 19:42

Hello. I am putting together a Windows 98 gaming PC. It has come to my understanding that these older systems use more power on the 5v rail rather than the 12v rail?
I managed to find a Seasonic PSU with 20A on the 5v. So my question will 20A on the 5v be enough for my setup?

Setup:
Motherboard - ABit BX133-RAID
CPU - Pentium iii 933mhz
GPU - 2x Voodoo ii sli and Matrox Millennium 2
Sound - Sound Blaster Live
And some CD, DvD drives

Thanks

Reply 1 of 1, by Archer57

Posted on 2025-07-25, 00:34

Archer57 Offline

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Joined: 2025-05-03, 18:30

What's important is not necessarily how much, but how well the PSU will handle such atypical load (all 5v and 3.3v, almost no 12v). Needs to be DC-DC based, not group regulated.

Other than that such system would not require a lot of power - voodoo cards should be around 10w/card IIRC, CPU is <30W. Should run just fine on any modern DC-DC power supply, but i'd probably go for something that has at least 15A just to be safe...

Group regulated PSUs would not be good because they'll have trouble keeping voltages in range under such load, no matter how high 5V rated current is.

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