RandomStranger wrote on 2022-07-26, 19:52:

TrashPanda wrote on 2022-07-26, 15:12:

blackmasked wrote on 2022-07-26, 14:48:

I've had the impression that for Pentium 3 / 4 / early Athlon era it was +12V that was more important.

Anyway, I'd rather use a new PSU, but very few new power supplies have strong enough rails that are important for retro build and no molex / floppy cables.

In Pentium 1 / 2 builds that I have I ended up using more modern PSUs with 120mm fans that run nice and quiet, but again, lack of molex power cables is an issue and SATA-Molex adapters create a bit of a mess.

P4 wants a ton of +12v where as P3 and Athlon XP want as much +5v as you can give them, the higher end Barton's really do like +25Amps on the +5v rail but with a stripped down setup you can get away with less. (P3 is far more forgiving with +5v Amps as it doesnt draw anywhere as much power as a loaded Athlon XP system can, especially over clocked ones)

This is just my experience and I have a number of these systems, there have been others who have gotten Athlon XP to run just fine with modern ATX PSUs but I have no idea if they are running a lean setup that isn't hogging the +5v rail. I would guess that if they are running a setup with out Spinning Rust or Optical drives/Floppy Drives then the load on the +5v rail would be considerably less, a GPU with its own Power connector would also help a modern ATX PSU deliver the needed +5v Amps.

Athlon/Athlon XP are mainboard dependent on that regard. Some late Socket A boars (like my MSI KM3M-V) have the same type of 12V auxiliary CPU power connector as more modern systems have. Though with those late boards you have to give up on ISA.

Ahh that would explain it, I didn't realise that any Athlon XP boards had that connector !

Learn something new everyday on this forum 😁

I just tried an experiment today: I have my Amptron M930LMR (SiS 645 2.8 533/512 Radeon 9800SE unlocked with Omega drivers, Win98SE, SSD) setup with an L&C B350 ATX 350 watt PSU with a 35 amp +5, and it works fine. I was given a Corsair CX430 that's nice and new, has a large cooling fan on the bottom (a big plus), and a 20 amp +5. I tried using it instead thinking that the 20 amp +5 ought to be good enough, but partway through running 3D Mark 2001 the system would crash with colored lines on the screen that looked scarily like a failing video card. This happened twice, so I swapped in the old L&C unit, and everything was fine again. Remember, this system doesn't have a P4 connector, so it's about as reliant on the +5 as your average Socket A system.

timw4mail wrote on 2022-07-26, 18:28:

blackmasked wrote on 2022-07-26, 16:42:

By the way, what do you guys do whan it comes to using modern PSUs in retro builds that lack molex/floppy connectors? Do you use adapters or do you desolder/cut everything unnecessary and replace them with molex?

I just use adapters. SATA -> floppy and Molex -> floppy connectors are probably fine even with questionable adapters due to the low power usage. SATA -> molex is iffy.

I've been thinking for a while getting modern PSUs and replacing the SATA cables with molex and floppy taken from crappy/dead old PSUs. It takes some soldering, but the result should be better than adapters.

RandomStranger wrote on 2022-07-27, 06:16:

timw4mail wrote on 2022-07-26, 18:28:

blackmasked wrote on 2022-07-26, 16:42:

By the way, what do you guys do whan it comes to using modern PSUs in retro builds that lack molex/floppy connectors? Do you use adapters or do you desolder/cut everything unnecessary and replace them with molex?

I just use adapters. SATA -> floppy and Molex -> floppy connectors are probably fine even with questionable adapters due to the low power usage. SATA -> molex is iffy.

I've been thinking for a while getting modern PSUs and replacing the SATA cables with molex and floppy taken from crappy/dead old PSUs. It takes some soldering, but the result should be better than adapters.

Sata > Molex / Molex > Sata adaptors have a rather bad history, I have personally seen a number of these nasty little hacks go sideways and kill components, usually in a shower of sparks, heat, magic smoke and melted Molex connectors. So I too would consider doing what you suggest, with the right splicing and heat shrink it should be a lot more robust than a chintzy chinese adaptor made by the lowest bidder.

TrashPanda wrote on 2022-07-27, 06:47:

RandomStranger wrote on 2022-07-27, 06:16:

timw4mail wrote on 2022-07-26, 18:28:

I just use adapters. SATA -> floppy and Molex -> floppy connectors are probably fine even with questionable adapters due to the low power usage. SATA -> molex is iffy.

I've been thinking for a while getting modern PSUs and replacing the SATA cables with molex and floppy taken from crappy/dead old PSUs. It takes some soldering, but the result should be better than adapters.

Sata > Molex / Molex > Sata adaptors have a rather bad history, I have personally seen a number of these nasty little hacks go sideways and kill components, usually in a shower of sparks, heat, magic smoke and melted Molex connectors. So I too would consider doing what you suggest, with the right splicing and heat shrink it should be a lot more robust than a chintzy chinese adaptor made by the lowest bidder.

I meant soldering them directly onto the PSU PCB in place of the original cables replacing them completely.

RandomStranger wrote on 2022-07-27, 07:11:

TrashPanda wrote on 2022-07-27, 06:47:

RandomStranger wrote on 2022-07-27, 06:16:

I've been thinking for a while getting modern PSUs and replacing the SATA cables with molex and floppy taken from crappy/dead old PSUs. It takes some soldering, but the result should be better than adapters.

Sata > Molex / Molex > Sata adaptors have a rather bad history, I have personally seen a number of these nasty little hacks go sideways and kill components, usually in a shower of sparks, heat, magic smoke and melted Molex connectors. So I too would consider doing what you suggest, with the right splicing and heat shrink it should be a lot more robust than a chintzy chinese adaptor made by the lowest bidder.

I meant soldering them directly onto the PSU PCB in place of the original cables replacing them completely.

That works too 🤣, the full renovation.