With my Dual Intel Pentium IIIE (Coppermine) @ 1.00GHz system +5 volts maxes out at 18.063 amps so I expect a 20 amp PSU will be fine.

The GPUs are S3 Savage 2000 [Diamond Viper II Z200] + Matrox Millennium G450 Dual Head.

It also has an Adaptec AHA-2940U2W Ultra2 SCSI Controller with DEC DSP3210S + QUANTUM ATLAS IV 9 WLS SCSI drives

I have seasonic Focus+ 20A 5V PSU working fine with P3 1Ghz, Geforce 4 TI4600 and voodoo2 SLI, so I think 20A should be fine at least for your P3 system.

On a MSI K7N2 Delta-L 2003 someone has placed an old 2003-04 Antec TrueBlue 480W(v1) which has 5V 38A. (Almost 40A).
- It works and BIOS measurements are ok.(Even when some sites say bad things about some TrueBlue versions.)
In it would a brand new 2018-2020 PSU with 5V: 20-,25-,30A work ?

Should manufacturers start making these 5V 30-40A PSUs again and make them more common ?

Is Bequiet! PSU calculator correct in 5V ? You can even select socket A Athlons and ATI 9800 Pro in it.
https://www.bequiet.com/en/psucalculator

I'm using Seasonic SS-350ET (20A on 3.3V/5V) with Coppermine PIII 933MHz and GeForce4 MX440, no problems so far.

user33331 wrote on 2020-05-16, 05:20:

Should manufacturers start making these 5V 30-40A PSUs again and make them more common ?

https://www.bequiet.com/en/psucalculator

That seems extremely unlikely, as there's been a push by Intel to eliminate the 3.3V and 5V rails with the ATX12VO spec.

https://www.gamersnexus.net/guides/3568-intel … facturers-think

I always thought the issue with newer PSUs isn't that the 5V rail is weak, but that the 12V rail is used for regulation, which is normally not much loaded on older systems, thus making the 5V unstable or out-of-spec?

user33331 wrote on 2020-05-15, 14:25:

Hello - Processor: PIII-S: 1.266 GHz, SL5QL. - Basic graphic card: GF4 MX440 or GF5 FX5600. Will a basic 550W Seasonic 5V 20A or […]
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Hello
- Processor: PIII-S: 1.266 GHz, SL5QL.
- Basic graphic card: GF4 MX440 or GF5 FX5600.
Will a basic 550W Seasonic 5V 20A or a Corsair, Be quiet! 5V 25A work fine ? No need for 5V 30A ?

- I also have this MSI K7N2 Delta-L (AMD Athlon motherboard)
So with this I need 5V 30A power supply I'm right ?
Old Durons work with 5V 20A and for larger Athlon XP: 2400-3200+ I need 5V 30A.

In a one very old project I used: 600 MHz Duron, Voodoo 3 AGP and BeQuiet! 5V 30A power supply just to be sure.
Confusing is 5V20A enough ?
New Seasonic's with 5V 30A are 1000W power supplies.
New Be Quiet! Dark Pro 11 and Straight Power 11 are with 5V 25A.
New Corsair RM--X and RM--I are with 5V 25A.

I believe PhilsComputerLab has already answered this on YouTube.

5V is mainly a concern for certain ISA cards and AMD Socket A CPUs. If it's a late-90s rig with late/no ISA cards, then any modern PSU is fine. In my Pentium III-S and 4 builds, I use budget modern Corsair PSUs, no issue.

Now, I do use a 5V-capable PSU from StarTech that you can buy brand-new in my Pentium MMX 233 system, just in case. (product page - https://www.startech.com/Computer-Parts/PSUs/ … ply~ATXPOWER300) Right now, due to the human malware situation, JayzTwoCents has noted that there appears to be a PSU shortage in the retail market, so finding one online new for a good price (my two units set me back $35) is going to be a bit challenging, but give it a few months and hopefully they'll be back in stock.

the_ultra_code wrote on 2020-05-16, 21:21:

5V is mainly a concern for certain ISA cards and AMD Socket A CPUs.

I don't see how you can say this about AMD Socket A CPUs given my Dual Socket A system maxes out +5 at 13.813 amps.

All in all I feel the sensible solution is have at least one PSU that reports what currents are being used and use it to decide what is needed.

red-ray wrote on 2020-05-16, 22:04:

the_ultra_code wrote on 2020-05-16, 21:21:

5V is mainly a concern for certain ISA cards and AMD Socket A CPUs.

I don't see how you can say this about AMD Socket A CPUs given my Dual Socket A system maxes out +5 at 13.813 amps.

All in all I feel the sensible solution is have at least one PSU that reports what currents are being used and use it to decide what is needed.

Fair enough. I'm just repeating what PCL said (I know, very intelligent I am 😜)

https://youtu.be/efK7mw8eYiE

red-ray wrote on 2020-05-16, 22:04:

All in all I feel the sensible solution is have at least one PSU that reports what currents are being used and use it to decide what is needed.

I have a few newer PSU and the Corsair HX 750 does not seem to have AIO reporting, neither does the Antec TPC750. Do you have a list of known PSU models that do support the AIO ?

Very rare I think only Thermaltake gives real time smart info. You can use mobile phone app.
+ Does Corsair's RM(i) models and such with USB Corsair link show amperage draw ? I don't understand Corsair link even after watching introduction guides. I tried to find if I can put the fan always ON with RM(i) models for better air flow. There is a fan test button on the PSU so if I put a tape over that button does the fan spin always ?

If you're a bit handy you can build your own measurement setup:
Get an ATX cable extension and two DC ammeters: one in the 30A-50A range and one in the 10A-20A range (both continuous).
Cut all the yellow wires on the extension and connect them to your 10A-20A ammeter. This will show +12V power draw.
Next do the same with the red wires and your 30A-50A ammeter. This will show +5V power draw.
Get a third ammeter and use it on the orange wires if you want to figure out +3.3V power draw.
Get a fourth ammeter plus 4/8pin extension in case you want to measure a 4/8pin mobo connector. Same for 6/8pin PCIe. Keep in mind PCIe power connectors also have sense pins so use the proper wires.
It's a bit more complicated than Phil's guessing game but it's a nice addition to any test bench and delivers much better results.

Horun wrote on 2020-05-17, 00:38:

Do you have a list of known PSU models that do support the AIO ?

With the Corsair PSUs it's the ones with an i at the end and with Thermaltake it's the DPS models. In general check if the PSU has a USB connection.

The full list of PSUs that SIV supports in on Menu->Tools->Link Limits and if you have a PSU with a USB connection that SIV does not report I should be able to add it, does your Antec TPC750 have a USB connection?

I know SIV should report things OK on Windows 98 or Windows 2K and later, but I am unsure about Windows 95. You could always use a different system to report the PSU readings.

Getting Corsair AXi PSUs to report may be impossible on W9x as I don't think there is an SIUSBXP driver, but I managed to find a Windows XP SIUSBXP driver. If you have a CLCC you could connect some AXi PSUs via that so it end up as a HID device. This is what all the other PSUs I have come across are meaning Windows will use it's standard HID driver.

"Getting Corsair AXi PSUs to report may be impossible on W9x as I don't think there is an SIUSBXP driver"
- Will Corsair RMi i-series work in Windows 98se with USB-control to show data ?
- When setting the PSU fan mode to always ON with Corsair RMi does the usb cable have to be always connected or does the PSU have memory so it remembers the fan settings made after unplugging the USB cable connection ?

user33331 wrote on 2020-05-19, 17:23:

"Getting Corsair AXi PSUs to report may be impossible on W9x as I don't think there is an SIUSBXP driver"
- Will Corsair RMi i-series work in Windows 98se with USB-control to show data ?
- When setting the PSU fan mode to always ON with Corsair RMi does the usb cable have to be always connected or does the PSU have memory so it remembers the fan settings made after unplugging the USB cable connection ?

Yes all the others should be fine and it's just the AXi PSUs that need the SIUSBXP driver so are problematic. All the others I have come across are HID devices and use the standard Windows HID drivers.

As to what RMi PSUs do I don't know and as I don't have any can't check. It may well depend of if the mains power is removed.