Here, this should answer any questions people might have as to what architecture they need to compile for, given the make & model of a CPU. Anything without CMOV is a 586 as far as I'm concerned, so that's what I'm putting here. I've included some weird stuff to cover the oddball systems as best I can. I *think* I've got it covered but we'll see...
Anyone with something questionable that isn't covered here, start a thread in the appropriate place and PM me a link so I know to weigh in. I'll be there!
386,486 = don't even bother. If it has an FPU*, then you can run some kind of antique discontinued distro IF your other hardware specs will support it AND you can track down a download link that still works. Generally speaking, if you have anything earlier than an original Pentium, you're stuck with long-gone floppy-based distros. If you have a system without an FPU* then I'm sorry but you're basically SOL -- FPU* emulation in software is a kernel thing, and the distros that include that are phenomenally rare. It just bogs everything down horribly anyways...
If you are super doober out-of-your-mind desperate for the Linux experience on a relic, grab a copy of XWOAF from goingnuts here on the forum (you'll probably have to PM him, his website [goingnuts.dk] doesn't always work) and write it to a floppy (it's a disk image, so if you're not comfy with 'dd' you'd better get there). Then pray you have both a 486 with an FPU* (486SX+487, or 486DX) AND 24meg RAM, and if your prayers are answered it will boot for you... if, unlike my copy, it's not a corrupt disk image...
That said, if you actually *do* want to boot XWOAF on a 486 or similar, (a) please PLEASE post pics, and (b) you probably ought to get that checked
...now, onto the useful stuff...
Pentium 1 = 586
Pentium Pro = 686 (it was expensive and crappy, nobody cares)
Pentium 2 = 786
Pentium M = modified 686 (!)
AMD K5 = 586 (does anyone even remember this thing?)
AMD K6-anything = 586
(this includes K6 [AFAIK], K6-2, K6-2+, K6-III aka K6-3D+, K6-3+)
AMD Athlon (original aka K7) = 686 [AFAIK]
Cyrix 6x86 = 686 (OH GOD CYRIX
)
(note for everyone -- don't use Cyrix crap, the FPU* inside is so pathetic that it's essentially marketing hype and nothing else!)
IDT WinChip = 586 (don't use this, either, it's FPU* is actually *worse* than Cyrix's stuff... I really don't know how they did that...)
VIA Cyrix III = 686 (Via bought both IDT/Centaur and Cyrix, and their crap isn't any better. Trust me, I have some of it!)
VIA C3 = 686 (these are later-edition, renamed VIA Cyrix III CPUs)
VIA C7 = modified 686 (basically a Celeron M, only far crappier)
VIA Eden = pick either a C3 or C7 and take out what few brains are still there, so that it can be fanless. So either = 686 or = modified 686.
Vortex86 (original) = 586 w/o FPU*
Vortex86SX = 586 w/o FPU*
Vortex86DX = 586
Vortex86MX / PMX-1000 / Xcore86 = 586
Vortex86MX+ = 586
*FPU = Floating Point Unit, also called Numerical Processing Unit (NPU), Math Coprocessor, or simply Coprocessor or Coproc. A module (with Pentium and earlier CPUs, often a separate chip) that enables non-integer math computations for CPUs that don't normally support that. As a side-note, if you have a motherboard with a 486SX, and you put in a 487 coproc, you are actually adding a rebranded 486DX that becomes the CPU. You could technically remove the 486SX and as long as the "487" stayed, your system would not even notice... that trick *only* works with 486/487 pairings, though!
Pentium 4's are nasty beasts... you'd save a ton on your electric bill with this over a P4 anything -- enough to go to the movies every month or two, probably.