P2B with a daughtercard and a VIA C3 Ezra? It could run at 466 mhz some of the time. 😁

PIII 466 does not exist.

You come up with a billion ideas and parts in your post, that don't make much sense to me.

Here's my idea of an early PIII Katmai:

1) choose an early PIII from https://en.wikipedia.org/wiki/List_of_Intel_P … microprocessors (check release dates)
2) choose an early PIII compatible i440BX motherboard, such as the Asus P2B, P3B, AOpen AX6B or Intel SE440BX-2 (make sure the revision of the board that you're looking at is PIII compatible)
3) buy a nice beige ATX enclosure without front USB

Instead of 466 you can think of it as 4x66 = 266. That gives you a lot more options (Pentium II 266, K6 266, K6-2 266, 6x86 PR266, mII 266GP). 6x86 sounds especially good to me, since it's MX-PR266 which is pretty close to 4DX2-66 if you ask me. There are also a lot of Baby AT form factor Socket 7 boards that accept ATX power and 6x86 CPUs. Match made in heaven IMO.

SpectriaForce wrote:

PIII 466 does not exist.

Nope, but a P3-933EB does, and what happens if you clock its FSB at 66MHz not 133MHz? 😉

dionb wrote:

SpectriaForce wrote:

PIII 466 does not exist.

Nope, but a P3-933EB does, and what happens if you clock its FSB at 66MHz not 133MHz? 😉

Basically a PII-466..

For 466 you have several options:

- Celeron (Mendocino based) 466. The weakest of the lot but the only one that natively comes in 466 MHz flavour. Only available in S370 form, since Slot 1 variants top out at 433.

- Pentium III 933EB (Coppermine), runs natively at 133 MHz FSB so just halving it to 66 will give you a PIII 466. A bit crippled by the 66 MHz FSB, but you can still run memory at a higher speed. Available in Slot 1 and S370 variants.

- Pentium II 350 (Deschutes), overclocked to a 133 MHz FSB, again gives exactly 466. Many, if not most, should be able to overclock to that level. Exclusively Slot 1. Should be the fastest option, since it would run at 133 FSB. Most later BX motherboards should be able to run at that FSB without issues. You might need to pay some attention to picking a video card that can run at 89 MHz AGP speed if you go with a BX board, but again most nvidia or 3dfx cards should work ok.

- Pentium II 450 (Deschutes), Pentium III 450 (Katmai), Pentium III 600B (Katmai) or Pentium III 600EB (Coppermine), set to 4.5x103. Doesn't give exactly 466, but perhaps the BIOS will report it as such anyway. The Deschutes and Katmai chips are exclusive to Slot 1, while the PIII 600EB comes in both slot and socket variants. 600EB will be easily the most energy efficient of this quad, but other than that they should give you virtually identical performance, somewhere between the underclocked PIII 900EB and overclocked PII 350.

SpectriaForce wrote:

PIII 466 does not exist.

True, but as frudi and dionb posted, there are ways to get close enough with a slight FSB change

SpectriaForce wrote:

You come up with a billion ideas and parts in your post, that don't make much sense to me.

Yep! It's madness. 😈 Truthfully, I have some parts that I want to use, some compatibility restraints, and a gap in my hardware lineup -- and so it became a puzzle to try and solve. There's no legitimate reason I have to do it this way, except it seemed like an interesting challenge.

SpectriaForce wrote:

1) choose an early PIII from https://en.wikipedia.org/wiki/List_of_Intel_P … microprocessors (check release dates)
2) choose an early PIII compatible i440BX motherboard, such as the Asus P2B, P3B, AOpen AX6B or Intel SE440BX-2 (make sure the revision of the board that you're looking at is PIII compatible)
3) buy a nice beige ATX enclosure without front USB

1 & 2: My main concern is that I don't have much experience with that gray area between P2, P3, and the early Celerons. I'm not entirely sure what I can buy would work -- and maybe the answer is: You won't know for sure until you try. If so, well, so be it... But I thought maybe someone would have some pointers.
3) No. Defeats the point of the challenge, and I have too many cases (that I refuse to part with) as it is. 😉

appiah4 wrote:

Instead of 466 you can think of it as 4x66 = 266. That gives you a lot more options (Pentium II 266, K6 266, K6-2 266, 6x86 PR266, mII 266GP). 6x86 sounds especially good to me, since it's MX-PR266 which is pretty close to 4DX2-66 if you ask me. There are also a lot of Baby AT form factor Socket 7 boards that accept ATX power and 6x86 CPUs. Match made in heaven IMO.

Yep, thought of both, but no can do. I haven't had much luck getting BeOS r5 to run stable on any S7 in my inventory yet -- and that's a priority for this build. I used to run it as my daily on a P2-350, though. Also, modern Linux on a Pentium is getting to be more trouble than it's worth. A Celeron 266 would technically work, it's just so slow.... 😉

frudi wrote:

For 466 you have several options:

I'm giving the Mendocino option a shot, mostly because I found a VIA 693 board with a 466 CPU for $30, so I figured that would be a good place to start. I'm curious to see if it will run on the Zida Tomato 691-based board I also found, but I'm not sure the multiplier will go that high. (The manual does not list a manual setting of 7x, but maybe in jumper less mode?)

So either of these would work, but I'm also still curious about maybe the Katmai or CuMine options, since I have a Slot 1 P2 and a S370 Tualatin, but not a Slot 1 P3... That's where my knowledge of that gen falls short -- but it sounds like a BX board should work then? (I have one to try, I just don't have the CPU.)

Also have my eyes peeled for an AT P3 board, but those have got to be pretty few and far between... I would think BX might be the last stop.

The most downclockable Pentium III you can get is 533/133. Exist both in Katmai and Coppermine lineups. Some motherboards can work at 50mhz, so Pentium III 200mhz is achievable.

Also have my eyes peeled for an AT P3 board, but those have got to be pretty few and far between

Most of them has suboptimal amount of slots, so why bother? Heck, Acorp even made Tualatin ready AT board, but the layout is just horrible - AGP, 3 PCI and 1 ISA (shared with PCI).

SirNickity wrote:

Also, modern Linux on a Pentium is getting to be more trouble than it's worth. A Celeron 266 would technically work, it's just so slow.... 😉

Debian 8 runs fine on my P166MMX test rig so does Duvean and Slackware. Stretch and Buster have i386 ports that support 1586/i686 arch. In fact using the compatible software such as Window Maker, ICEWM and other are as fast as there 1999 siblings. And you have the added support for things like pci nics, wifi and usb 2 out of the box.

I've done some tests of various Linux distros from 1999 on wards. *nix software and systems

The Serpent Rider wrote:

The most downclockable Pentium III you can get is 533/133. Exist both in Katmai and Coppermine lineups. Some motherboards can work at 50mhz, so Pentium III 200mhz is achievable.

Also have my eyes peeled for an AT P3 board, but those have got to be pretty few and far between

Most of them has suboptimal amount of slots, so why bother? Heck, Acorp even made Tualatin ready AT board, but the layout is just horrible - AGP, 3 PCI and 1 ISA (shared with PCI).

I'm 100% OK with that. AGP Video, PCI net, PCI SCSI, ISA sound. Done. I might sometimes want to plug in an ISA science fair project, so a second slot would be nice. Looking on Ebay, there are a bunch of Acorp boards labelled "6BX/VIA/ZX86" with two ISA slots. That would be ideal. But... uhm... is that a 440BX, VIA, or 440ZX northbridge? Can't tell on account of the heatsink. If it's a BX (or I guess even a ZX) then it's close enough to my P2B-B, except for perhaps better BIOS support of P3 CPUs.

Might have to order a Katmai 450 and just see what happens...

A slotket adapter + P3 with a 7x multiplier would be the easiest. You can find slotted version of the coppermine 700mhz EB but they are pretty rare and expensive, as they are the fastest officially supported for the platform.

133mhz capable slot 1 boards are a bit expensive, but another option with a 3.5x multiplier chip (probably katmai).

My first S370 VIA691 board arrived, but I'm waiting on the other S370 board with the Mendocino CPU to show up from some place that will probably get me put on some kind of watch list. 😉 I'm really skeptical that any of these BX-era boards are going to support a 7x multiplier -- I keep going through manuals and looking at silkscreened jumper tables and the highest I see is 6x. Who knows what that Mendocino will be running at.

In the meantime, I bit on a Katmai 450 slot 1 CPU as well. I'll try that in my P2B-B. I don't really want to use that board for this build (bought it as a backup for the Totem in my main PII build) but at least I'll be able to compare the two. The more I think about it, the more a 103x4.5 makes sense based on the other hardware I have.

Those Acorp boards, BTW, all look to be VIA691 or similar. They have visible VIA southbridge chips, and I highly doubt they're mixing those with an Intel northbridge. I did find one that looks to be a BX board. Quite a bit more costly though -- about neck in neck with another P2B-B.

I'm 100% OK with that. AGP Video, PCI net, PCI SCSI, ISA sound.

AGP card might take two slots though.