Technically, it's the same silicon, even Geode NX.

Yeah, a lot of mobiles, not all though, and IDK specifically about these, but many are just very good binned cpus ran at a lower freq and voltage. Sometimes they come in a different package. But a lot of them as said are the same silicon.

Some/many have registers or IDs that announce to cpu ID programs and bios that they have been binned as a mobile.

"Desktop Replacement" notebooks became a thing early this century, not as small, not as light, more power hungry so battery life was not great, but inteded for ppl who wanted a cheaper machine in a more compact formfactor. Or one, much like the old "Lunchbox" portables that could be moved from place to place but didn't really need to fit on an airline seat tray or be flipped out and ready to go in a meeting etc.

Many of these used desktop CPU, Intel for a couple of years was really lagging with it's mobile speeds and availability so if you needed 3Ghz of Pentium 4, you weren't gonna like the 1.6ghz mobile on offer. AMD had a slight gap between K6 plus being fast enough and the Athlons being cool enough, but rather than out of necessity to get the clockspeeds there were still AMD desktop in portables just for the cost saving. I have a Gateway machine that has a desktop Sempron s754 in.

What is the way to identify exactly what's what?
This? AXDA3200DKV4D
Or the stepping codes? AQXCA AQXDA AQZFA
We shall soon find out... hopefully. Seller completely unresponsive, but I won the auction.

It's the "part number" that matters. I didn't catch which laptop you're getting, but it'll show different depending on that. They have so many variants of die quality, so each model had quite different "mobile" dies.

The list on wikipedia is what I use to hunt them down by "part number". https://en.m.wikipedia.org/wiki/List_of_AMD_A … n_XP_processors