Choosing PSU for Pentium 3 system \ VOGONS

Choosing PSU for Pentium 3 system

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First post, by WildW

Posted on 2023-10-10, 14:22

WildW Offline

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I'd like to replace the 25 year old power supply in my Pentium 3 system (450Mhz slot 1, Voodoo 3 2000). From what I can see on other threads these use so little power that "any" modern PSU should be able to cope, but I wonder if anyone has any wisdom to pass on regarding what to go for? I don't think I need -5V for my ISA sound card with some OPTi chipset I don't remember.

I did try a PSU swap some years ago with some random spare power supply I had, and the computer/PSU shut itself off again after a couple of seconds every time, hence me asking for advice! I use a real IDE hard disk and CD-ROM drive, so hopefully enough to keep the 12V rail loaded?

Reply 1 of 5, by gmipf

Posted on 2023-10-10, 14:53

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Corsair CV Series CV650 Dual EPS 650W ATX 2.31 (CP-9020236-EU) has 24A on the 5v rail. But in your case everything 20A and higher should be ok. Just look here: https://cultists.network/140/psu-tier-list/
and don't buy anything lower than C tier and anything from speculative positions. 3.3v and 5v rails should be at least 20A.

Here is more to the subject:
5V/3.3V Rail Current

Reply 2 of 5, by APT97

Posted on 2023-11-30, 13:51

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One thing to bear in mind with the new Corsair PSUs is that the extra 4 pins of the ATX power connector can't be detached, it just comes as one solid 24-pin connector. Probably not an issue as long as there aren't any components on the motherboard right next to the power connector like a capacitor or something, but I think it's still worth mentioning.

What's more annoying is that the CX550 that I bought recently didn't have a floppy power connector at all, and only two Molex connectors. That means you have to use a Molex to floppy adapter (if you're using a floppy drive) leaving you just one Molex. I was very disappointed by this, I hope other PSU manufacturers don't start going in the same direction and ditching legacy connectors.

So for those reasons I would avoid the latest Corsair PSUs for retro PCs, putting aside the whole 5v/3.3v issue.

MSI MS-5156 430TX, PMMX 233, Matrox Millenium 1, Voodoo 1, ESS AudioDrive 1868f, 32MB RAM
MSI MS-6163 440BX, P3 1ghz, Gf4 Ti 4200 8x, Voodoo 2, Sound Blaster Live, 256MB RAM
Asus P8Z77V-LX, i7-3770, GTX 750 Ti, X-Fi Titanium, 8GB RAM

Reply 3 of 5, by bobsmith

Posted on 2023-11-30, 15:02

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I use a brand new Thermaltake 500W PSU in my P3 build along with a Cooler Master N200 case, specs in my signature. Works great so far and haven't noted any issues, but had to use a Molex to floppy adapter as APT97 mentioned. Additionally, you must have a 24-pin to 20-pin ATX power converter if your specific PSU doesn't have a 24 pin that breaks away to 20.

Main PC : MSI PRO B650M-P Ryzen 5 7600, 32GB DDR5-5600, XFX RX 7600
P3 build : ASUS CUSL2-C, Pentium III @ 733MHz (Coppermine), Voodoo3 3000 AGP, 384 MB SDR-100, Audigy 2 ZS, Netgear GA311

Reply 4 of 5, by darry

Posted on 2023-11-30, 15:07

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APT97 wrote on 2023-11-30, 13:51:

One thing to bear in mind with the new Corsair PSUs is that the extra 4 pins of the ATX power connector can't be detached, it just comes as one solid 24-pin connector. Probably not an issue as long as there aren't any components on the motherboard right next to the power connector like a capacitor or something, but I think it's still worth mentioning.

What's more annoying is that the CX550 that I bought recently didn't have a floppy power connector at all, and only two Molex connectors. That means you have to use a Molex to floppy adapter (if you're using a floppy drive) leaving you just one Molex. I was very disappointed by this, I hope other PSU manufacturers don't start going in the same direction and ditching legacy connectors.

So for those reasons I would avoid the latest Corsair PSUs for retro PCs, putting aside the whole 5v/3.3v issue.

Startech makes adapters for 24-pin to 20-pin ATX power connectors.

Reply 5 of 5, by The Serpent Rider

Posted on 2023-11-30, 15:47

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APT97 wrote on 2023-11-30, 13:51:

That means you have to use a Molex to floppy adapter (if you're using a floppy drive) leaving you just one Molex.

You can use splitter adapter.

I must be some kind of standard: the anonymous gangbanger of the 21st century.

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