VIA and especially SiS chipset are more suitable for Geode processors.
Advantage of Geode (besides low power) is ability to change multi on-the-fly from software (CrystalCPUID).
That PSU should be great choice for Athlon 1400, as it offers 32A on 5V rail. Don't be too concerned with MBO voltage readings, it's within acceptable margin.

The Thunderbird 1400 is a great CPU (albeit, very power hungry and hot). Having said that, don't think there's any reason to use it in a retro PC other than nostalgia and/or the desire of having an end-of-an-era PC (one of the best eras that AMD has had, if I might add).
Under normal conditions, I would suggest a Thoroughbred Athlon XP (one with unlocked multiplier), which would give you great speed flexibility (particularly useful for building a time machine PC that can cover almost 20 years of games, including very old DOS titles), however, since you have an nForce 2 board ... that's not really an option.
So, my suggestion in this case would be to just aim for the top and get an Athlon XP 3200+ 😀 It's more or less as power hungry/hot as the Thunderbird 1400, but much faster.
Another option is the Athlon XP 2600+ (barton / 333 FSB). I have two of those and they overclock like crazy (2.3 GHz just by increasing the FSB from 166 to 200).

It should be ok. I have one PC with an Athlon 1400 (an older kt133a with sd-ram) and confirm its a capable CPU. I haven't tried Linux with it, but your results suggest its up to the task. Definitely draws the power though, but it shouldn't be a problem

in performance terms i think it on a par with similar speed pentium 3 and early pentium 4 and its not all that much slower than the earlier version of the amd athlon xp range

stef80 wrote on 2021-04-19, 10:03:

VIA and especially SiS chipset are more suitable for Geode processors.
Advantage of Geode (besides low power) is ability to change multi on-the-fly from software (CrystalCPUID).
That PSU should be great choice for Athlon 1400, as it offers 32A on 5V rail. Don't be too concerned with MBO voltage readings, it's within acceptable margin.

Thanks. Building this config with the Geode cpu sound somehow cool cause it's quite uncommon to see one used of that generation, I bought it long time ago but never tested it a lot and this Nforce2 boards seems to not like it probably for the low vcore who knows why. At the end it should not be much different than any Athlon XP Mobile.

Instead about this Athlon 1400, I've seen the cpu should use 60/70W of power itself, I was expecting more but these PSU are great and really needed for this builds. It's funny how this old "beast" like also the Barton or the Prescott are still capable nowdays to work beside their feature limitations on both an old o.s. and a modern one.
I remember the lack of SSE was a common problem on linux side but I might be lucky with the distro choice but everything works and tried with a Radeon 9500 64MB even VDPAU video decoding works too. The RV100 instead is a choice to make it a bit more time correct (the mobo isn't obviously) and less power draining.. it's a gpu very power conservative and OpenGL works too with the great open source radeon module. On Win ME instead I think I'd choose different gpu's having more driver support for it.. like a Matrox G450/G550 or a Savage4 Extreme or some early Geforce series.
The Athlon 1400/133 sure sounds like the Athlon 1000 on Slot.. one of the latest "warrior" of its own generation. 😀

Geode is actually recognized as "AMD Mobile Athlon XP-M".
I have it on ECS K7s6a motherboard (SiS 745). I migrated from Duron 1300 to Geode NX 1750. Temps went from 55°C to low 30s in idle mode.
And there is also less strain on motherboard VRM (core voltage 1.75V -> 1.25V ).

Yeah that was one of the early target for this config. Anyway I think something in fact isnt' perfectly working with modern distro too.. modern browser already incredibly works but web pages with media like youtube seems to crash the tab. I suppose the lack of SSE1 (not to mention 2) is somehow involved into this. Not like this was the target of this machine but it was nice to see it running even modern pages. Still most ones seems to load well and incredibly fast.

I might try some Athlon XP on it but I wanted this config to be a bit closer to the old tech than the new one.

Then you need a different motherboard. This is one of the last generation of SoA boards. Extremely picky when it comes to memory, but fast if you find some it's prepared to be stable with. It's three full years younger than the A1400C though (early 2004 vs early 2001), so not even remotely "closer to the old tech". SATA, AGP 8x and dual-channel DDR-400 were awesome when new, but putting an older CPU in here and claiming it's closer to old tech is like putting the engine from an '80s Golf in a late 1990s fully kitted out Octavia and claiming it's the real GTI experience 😜

dionb wrote on 2021-04-19, 11:22:

I might try some Athlon XP on it but I wanted this config to be a bit closer to the old tech than the new one.

Then you need a different motherboard. This is one of the last generation of SoA boards. Extremely picky when it comes to memory, but fast if you find some it's prepared to be stable with. It's three full years younger than the A1400C though (early 2004 vs early 2001), so not even remotely "closer to the old tech". SATA, AGP 8x and dual-channel DDR-400 were awesome when new, but putting an older CPU in here and claiming it's closer to old tech is like putting the engine from an '80s Golf in a late 1990s fully kitted out Octavia and claiming it's the real GTI experience 😜

😁 I know it, that's why I think I'll rewrite the component list.. it sounds a bit out of track with this cpu... it's that I had a couple of KT133 early Socket A boards that no longer worked so I only have this Socket A left and tested few times only.

All the Athlons are pretty nice. I'd love a Slot A K7 machine but at the moment I'm building a mobile Barton (2800+), part of my plan to build a few machine representing the greatest moments in PCs.

I still got a never tested Slot A mainboard but no cpu to try on it.. I might try to use maybe in future an Athlon 1000 on it but it seems a bit on the expensive collector side prices.