bestemor wrote:

Frankly I do not know how many Amps I really need. Was under the impression that perhaps 30A and 150w would be a minimum....(?) […]
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Frankly I do not know how many Amps I really need.
Was under the impression that perhaps 30A and 150w would be a minimum....(?)

Project1:
- Slot1 Pentium (400mhz normal, or 1400mhz slotket)
- 2 hdd (ide or sata w/adapter etc)
- 1 or 2 optical drives
- 2 floppy drives /or combo 3.5+5.25
- vga card, pci or agp (max GF 4600)
- 2 ISA soundcards, perhaps 1 pci
- some other PCI utility card(s)
- a couple of ram sticks

Project2:
- socket478 Asus mobo
- s479 processor on an adapter
- 2-3 harddrives
- 2 optical drives
- floppy, as above
- nvidia vga, some 6800GS-7900GTX agp
- 2-4 ram modules

+ some fans here and there...

The previous 'Pentium4' PSU(which currently needs an impossible to find model specific replacement ATX cable),
had 30A/3.3v & 45A/5v(275w combined), + 2 lines of 12v@20A(400w comb.), total max 500w.

But I don't think I'm willing to pay 300-400(!) euro a piece for a modern high power PSU, if that is what it takes to fill the gap.

Have noted the suggestions on finding used older PSU's. Maybe I'll delve some more into that.
But I am bit weary with these things, unless they were bought by myself...

P2/P3 CPU's aren't that power hungry and you don't really need a heavy 5V rail. So long as it's 20+ amps and it's a respectable brand you should be good. 5V rail becomes a problem when you deal with Athlon/Athlon XP

As for the P4 project, all P4 motherboards use 12V to feed the CPU, so 5V isn't really a problem here. Something like a $50 Corsair VS500 will be more than enough.

Hmm.... So what you are saying is, that it is basically the CPU which is the major deciding factor, and only vs the 5V line ?
(as 12V never is a problem anymore)

Then how much does the other additional components factor in vs 5V and 3.3V, I wonder...
(PCI cards, AGP, hard drives/DVD, etc...)

Found some power calculators online, but they don't seem to bother with anything other than wattage (no power distribution on Ampere or Volt).
- Maybe some answer could be gleaned from this then:

http://www.silentpcreview.com/article265-page4.html

https://forum-en.msi.com/index.php?PHPSESSID= … e;topic=93979.0

bestemor wrote:

Hmm.... So what you are saying is, that it is basically the CPU which is the major deciding factor, and only vs the 5V line ?
(as 12V never is a problem anymore)

The motherboard, to be more precise, as some socket A ones do use the 12v line for the CPU.

bestemor wrote:

Then how much does the other additional components factor in vs 5V and 3.3V, I wonder...
(PCI cards, AGP, hard drives/DVD, etc...)

It depends on the component as they can all use different rails. I do believe all disk and hard drives use 12V.

bestemor wrote:

Hmm.... So what you are saying is, that it is basically the CPU which is the major deciding factor, and only vs the 5V line ? (a […]
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Hmm.... So what you are saying is, that it is basically the CPU which is the major deciding factor, and only vs the 5V line ?
(as 12V never is a problem anymore)

Then how much does the other additional components factor in vs 5V and 3.3V, I wonder...
(PCI cards, AGP, hard drives/DVD, etc...)

Found some power calculators online, but they don't seem to bother with anything other than wattage (no power distribution on Ampere or Volt).
- Maybe some answer could be gleaned from this then:

http://www.silentpcreview.com/article265-page4.html

https://forum-en.msi.com/index.php?PHPSESSID= … e;topic=93979.0

As a rule of thumb you could say that all PC motherboards use 5v for their CPUs, except for P4 and later for Intel and A64 for AMD (there are some exceptions for Athlon XP, as already noted by Munx). Anything Pentium 3 and anything Athlon or older will be using 5v.

For Pentium 3 this isn't as much of an issue due to the lower power demand of this type of CPU (will run roughly 35W at the most) but anything that is called Athlon and fits into Socket A might need up to double that amount (70W or even a little bit more).

For Pentium 4, Intel decided it wanted P4 to use the 12v line instead and as modern PSUs still mainly are build for power delivery on mostly 12v, P4 is easier when needing a PSU for it.

Iirc anything GF7600 and up only used 12v and graphics cards from before that uses at least some of its power from the 5v line. This may even differ from manufacturer to manufacturer so details may be sketchy.

Some extra details can be found in this reply (see the attachment)

Got this PSU by a brand I don't know today - label shows a really beeffy 3.3V+5V rail, despite being somewhat newer (made in 2007). The unit itself is quite heavy too, so I thought I would take the gamble and grab it for 5 Euros.

This is what it looks from the inside. All the caps seem alright. I don't really know much about this stuff, does it look any decent?

Do yourself a favor and get rid of this unit. I had one, it never got to see a lot of action and still managed to blow up.

At its peak, it was powering a Core2Duo 6550 (65W TDP) and a Radeon 4850, so maybe it was pulling something like 250-300W on full load. The same unit went to my dad's PC for a few months, until it decided to blow up (thankfully it did not kill any other hardware). My dad's PC was (and is) even less of a powerhog, with an unlocked Phenom II x3 720 and... an integrated graphics card on the motherboard... It rarely sees any use since he always preferred to use his laptop (and later tablet) while drinking his coffee in the morning and evening.

Bottom line, never Trust no-name units.

Thanks for the info. Guess I'm sticking with the my FSP ones for heavy 5V needs.

Munx wrote:

Got this PSU by a brand I don't know today - label shows a really beeffy 3.3V+5V rail, despite being somewhat newer (made in 2007). The unit itself is quite heavy too, so I thought I would take the gamble and grab it for 5 Euros.

(3.3V x 32A) + (5V x 30A) + rainbows and unicorns = 360W on the 5V rail + 3.3V rail combined...

This unit seems totally legit... 😕

Skyscraper wrote:

Trust is known for branding Chinese fabricated items. […]
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Munx wrote:

Got this PSU by a brand I don't know today - label shows a really beeffy 3.3V+5V rail, despite being somewhat newer (made in 2007). The unit itself is quite heavy too, so I thought I would take the gamble and grab it for 5 Euros.

Trust is known for branding Chinese fabricated items.

(3.3V x 32A) + (5V x 30A) + rainbows and unicorns = 360W on the 5V rail + 3.3V rail combined...

This unit seems totally legit... 😕

F2bnp wrote:

Bottom line, never Trust no-name units.

I've had a rule of thumb for over 10 years now and one of them is "Never trust a Trust".

I dunno if it could be modified to work at least decently reliable, wasn't there a member here who used mostly recapped Deers and Allied PSUs?
There's plenty better choices for recapping though. FSP is one of them, also because they are quite common (or at least they used to back like 10 to 20 years ago as OEMs seemed to love them over here in The Netherlands).

Munx wrote:

Project1: - Slot1 Pentium (400mhz normal, or 1400mhz slotket) - 2 hdd (ide or sata w/adapter etc) - 1 or 2 optical drives - 2 fl […]
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Project1:
- Slot1 Pentium (400mhz normal, or 1400mhz slotket)
- 2 hdd (ide or sata w/adapter etc)
- 1 or 2 optical drives
- 2 floppy drives /or combo 3.5+5.25
- vga card, pci or agp (max GF 4600)
- 2 ISA soundcards, perhaps 1 pci
- some other PCI utility card(s)
- a couple of ram sticks

^ That's 150W peak system draw being generous. It's a pre-Pentium 4 so '+5V heavy' system. Any decent old-style '+5V heavy' 200W or more PSU in good condition will do.

Beware modern '+12V heavy' PSUs might not be able to regulate voltage on this '+5V heavy' system, unless the PSU uses DC-DC regulation (some with indy regulation and even some group-regulated with oversized minimum load resistors might also do).

Munx wrote:

Project2: - socket478 Asus mobo - s479 processor on an adapter - 2-3 harddrives - 2 optical drives - floppy, as above - nvidia v […]
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Project2:
- socket478 Asus mobo
- s479 processor on an adapter
- 2-3 harddrives
- 2 optical drives
- floppy, as above
- nvidia vga, some 6800GS-7900GTX agp
- 2-4 ram modules

^ That's 275W tops being generous. Any decent modern (and thus '+12v heavy') PSU of 350W or more will do.

Munx wrote:

Got this PSU by a brand I don't know today - label shows a really beeffy 3.3V+5V rail, despite being somewhat newer (made in 2007). The unit itself is quite heavy too, so I thought I would take the gamble and grab it for 5 Euros ...

Not too bad but crappy caps are crappy, and unless you like fireworks I wouldn't ask more than ~250W from that thing. Also looks dirty as hell, needs to take a shower.

Has anyone ever used the StarTech PS2POWER230 230W AT power supply? I've bought a lot of products from StarTech over the years and never had a problem with them and after reading this thread, I'm kind of wondering should I really go for their newer AT power supply or could I go with a semi modular ATX power supply like the PC Power & Cooling Silencer Series 400 Watt (PPCMK3S400)?

It's for a 33MHZ AMD 386 project I'm working on so its not a power hog, however 7 out of the 8 ISA slots will be filled with the following:

Video Card: Trident 8900D
Sound Card: Sound Blaster 16 - CT2940
System Controller: SAB-757
EIDE Controller: Promise DriveMax
Network: 3COM 3C509BC ETHERLINK III
SCSI: Adaptec AHA-1540/42CP
CD-ROM Controller: Future Domain IDE-16011

I'm planning on having 2 floppy drives (3.5 and 5.25) a CD-ROM drive, a Western Digital 2.5 GB 32500 Caviar Hard Drive & possibly a 250MB zip drive.

From what I'm seeing the modern power supplies only have 150 watts and 20-24 amps max on the 3.3 and 5 volt rails. So would that be enough for all the hardware on my system?

Also I'm curious which direction the fan is blowing in the modern power supply, is it intake blowing out the back or blowing out the top in which case it would be blowing upward into an empty area in the case.

TELVM wrote:

Munx wrote:

Got this PSU by a brand I don't know today - label shows a really beeffy 3.3V+5V rail, despite being somewhat newer (made in 2007). The unit itself is quite heavy too, so I thought I would take the gamble and grab it for 5 Euros ...

Not too bad but crappy caps are crappy, and unless you like fireworks I wouldn't ask more than ~250W from that thing. Also looks dirty as hell, needs to take a shower.

Agreed, but I wouldn't sign off on it until seeing what's used to switch the 5VSB rail!

zakurowrath wrote:

Has anyone ever used the StarTech PS2POWER230 230W AT power supply? I've bought a lot of products from StarTech over the years and never had a problem with them and after reading this thread, I'm kind of wondering should I really go for their newer AT power supply or could I go with a semi modular ATX power supply like the PC Power & Cooling Silencer Series 400 Watt (PPCMK3S400)?

FSP still sells new AT PSU: fsp fortron spi-250g
They cosy around 50 in the netherlands new. I usually just scavenge old AT computers for the AT PSU and inspect/clean them.

gdjacobs wrote:

... I wouldn't sign off on it until seeing what's used to switch the 5VSB rail!

I can tell from the second pic that it uses the dreaded 2-transistor scheme.

Richo wrote:

zakurowrath wrote:

Has anyone ever used the StarTech PS2POWER230 230W AT power supply?

I use one. No problems with it.

KT7AGuy wrote:

Richo wrote:

zakurowrath wrote:

Has anyone ever used the StarTech PS2POWER230 230W AT power supply?

I use one. No problems with it.

Awesome, looking at the specs of your machine if it can power that beast, it should have no problems with a 386, thanks KT7AGuy 😁

TELVM wrote:

gdjacobs wrote:

... I wouldn't sign off on it until seeing what's used to switch the 5VSB rail!

I can tell from the second pic that it uses the dreaded 2-transistor scheme.

Thanks! I see it by the cut in the head sink. Avoid, it's a potential board killer!

Richo wrote:

zakurowrath wrote:

Has anyone ever used the StarTech PS2POWER230 230W AT power supply? I've bought a lot of products from StarTech over the years and never had a problem with them and after reading this thread, I'm kind of wondering should I really go for their newer AT power supply or could I go with a semi modular ATX power supply like the PC Power & Cooling Silencer Series 400 Watt (PPCMK3S400)?

FSP still sells new AT PSU: fsp fortron spi-250g
They cosy around 50 in the netherlands new. I usually just scavenge old AT computers for the AT PSU and inspect/clean them.

Are there NOS or are these genuinely newly made products?
Interesting! They seem sold out here in The Netherlands though.

I did some more looking around and apparently there is also at least one FSP PSU still being sold with good amps on 5v, or at least according to tweakers.net
It's the FSP FSP400-70MP, link to FSP website itself. The specs can be seen by clicking on the right-most pic, but I found the rails were really low and when I saw it listed 300W max on 3.3v, 5v and 12v, I found that to be utmost peculiar...till I noticed they put the specs of the 300W model in there 🤣!

It's very expensive though for a 400W unit, but 30A on 5v is pretty much enough for any sA (maybe except for sA dual CPU).

Friends, can I ask your opinion about a good model for my cheap-gaming rig? I think 700-800ish w, for the load:

- ASUS P5B
- C2D E8500 3ghz (maybe a XEON quad modded for 775, X5450)
- 4GB/8GB DDR2 800mhz
- GTX480 VGA
- common SATA HD, SATA DVDRW

How much amperage do I have to seek? Can 700w be a good choice, regarding the insane GTX480 load?

Thanks!