Well, shoot, I think I've answered my own question: http://m.majorgeeks.com/files/details/setfsb.html

Looks like the ICS9250 clock controller is not supported... So I think I'll be getting another motherboard. Not terribly interested in a Celeron or slower C3.

I've got one of those Anaheim2 boards.

Some revisions supposedly have a jumper to switch between 66/100 Mhz and I think some even have a 133Mhz fsb option.

cyclone3d wrote on 2020-03-16, 21:15:

Some revisions supposedly have a jumper to switch between 66/100 Mhz and I think some even have a 133Mhz fsb option.

Do you happen to know what jumper that is or if I'd be able to populate a barren jumper on this board? or if it's clearly marked?

The revision I have doesn't even have the place where the jumper would go.

See here for the manual. Specs say 100Mhz : tbd
https://mbmanuals.retropc.se/manuals/125/Anaheim2.pdf

cyclone3d wrote on 2020-03-16, 22:56:

See here for the manual. Specs say 100Mhz : tbd

Yeah, I saw that... super bummer. I took the sort-of-broken English throughout the manual as a cue that maybe "TBD" didn't mean what it actually means. If that makes sense...

Well I did manage to find a confirmed C3-compatible board for less than stupid money. So hopefully it's not DOA or otherwise incompatible. It's an AZZA 810DMC, which does support a 100 MHz FSB. One contemporary review site I found, with Anandtech-like structure, showed it not posting at 100 FSB, but they were trying at that speed, it would overclock the Celeron they were testing, so since I'm running it stock and then underclock/undermultiplying(?) eventually, I'll take it with a grain of salt.

Found an archived page that has the BIOS for the Anneheim2:
http://web.archive.org/web/20021224041317/htt … iGem/index.html

jessenator wrote on 2020-03-16, 23:11:

cyclone3d wrote on 2020-03-16, 22:56:

See here for the manual. Specs say 100Mhz : tbd

Yeah, I saw that... super bummer. I took the sort-of-broken English throughout the manual as a cue that maybe "TBD" didn't mean what it actually means. If that makes sense...

Well I did manage to find a confirmed C3-compatible board for less than stupid money. So hopefully it's not DOA or otherwise incompatible. It's an AZZA 810DMC, which does support a 100 MHz FSB. One contemporary review site I found, with Anandtech-like structure, showed it not posting at 100 FSB, but they were trying at that speed, it would overclock the Celeron they were testing, so since I'm running it stock and then underclock/undermultiplying(?) eventually, I'll take it with a grain of salt.

What OS are you thinking of running?

i810 boards are generally not highly recommended for a number of reasons:
- (crappy) integrated VGA far too anaemic for 3D titles
- integrated VGA also takes 50% of memory bandwidth leaving CPU starved and performance much lower than with VGA with its own memory
- no AGP slot for something better
- AC'97 audio means no DOS support, although this board seems to have PC/PCI ("SBLINK") which would let you use something like a Yamaha YMF74x PCI card with native (no TSR) DOS.

By adding PCI VGA and audio you could get something half-decent working, but it would hardly let that C3 CPU shine at anything...

Well, to be completely honest, I'm being fairly casual about this whole thing (probably apparent, but I don't care 😉 ). Nevertheless, thank you for your insight.

I'm not too fussed about reaching the pinnacle of anything with this build; I just want to have fun with it and learn along the way, and at this point, just make sure I get a board that is at least compatible with the CPU I have, which apparently is far more involved than, say, an Intel chip of the era. I haven't sunk many dollars into this yet, and based on my search (for every motherboard on that wiki list), this was the least expensive option to wet my toes. I wasn't prepared to drop $90USD+ on the 4 or 5 other boards I saw on eBay within the USA. Not at this point anyway.

Have I spent more money in the past on other hobbies or in the vintage Macintosh world (where I started)? Sure have. But I learned from that particular shopping spree, sold a few things that didn't interest me anymore, and decided to dabble in the retro PC world which I'm doing here—with a limit. My goal is to run a DOS/98 machine and nothing too crazy. Again, I want this to be fun, so just getting it all together working is Goal Zero. Everything else is gravy.

TL;DR I want to build a retro DOS/98 PC which is better and easier to customize and maintain than my PC Compatibility Cards for my Macs, and have fun.

I think you need to set your priorities
If you want something decent to play games like Quake 3 well your probably looking at something around the P3 500 mark performance wise.
If you want dos gaming you want something with an isa slot for the sound card.

Anything else will be a compromise and like you said your already scraping in for some of the requirements.

Realistically your options are to play the games well
Intel: Slot1 suits this requirement well apart from down clocking for early games
AMD: Socket A allows down clocking but parts are harder to come by
ViaC3: at least a M/B that has an ISA slot

But to me it sounds like you really want a C3 based PC more then the games and fair enough they aren't common. but in that case I'd install the games around the system as your just dipping your toes for the moment.

To be honest, if you want to run VIA C3, your best bet is VIA EPIA 800. They are usually fairly cheap on eBay - I bought mine for 18 euro shipped!

It supports 100 and 133 MHz FSB.

It's a mini-ITX motherboard - fits into very small cases.

Integrated audio is DOS compatible.

PCI slot let's you install either a Voodoo 2 for 3Dfx only games or a "better" GPU for everything else.

Most EPIAs overclock easily to 1 GHz, at this clock speed it runs even the most demanding DOS games with gusto, it can also run a lot of classic Windows games fairly well (Fallout 2, HoMM 3, Planescape: Torment, Arcanum, Age of Empires etc.)

Like chinny22 said, don't try to span too wide a net with your PC. There ARE ISA motherboards that allow for Pentium III CPUs (I know because my Pentium III 450 system back in the day had two ISA slots) but I never was able to make that system a reliable DOS gaming one. It ran plenty of DOS games like DOOM, sure, but there were plenty of games that just wouldn't work properly.

If you go down that road anyway, a Voodoo3 card is a good bet since DOS compatibility for 2D games is pretty high with Voodoo cards.

red_avatar wrote on 2020-03-17, 23:12:

Like chinny22 said, don't try to span too wide a net with your PC.

jessenator wrote on 2020-03-16, 20:00:

I'm not looking for a SUPER WIDE range, like being able to play both ancient DOS games and then flip over and run Quake III Arena or anything. Just maybe get close to early PII capability

^-initial post post

😀 Exactly. I'm not looking for that at all; I think maaaaaybe Dark Forces II: Jedi Knight is about as modern I want to reach with this build, with a larger DOS library as the base. I'll hedge my expectations.

So it does sound like I'll need to hunt down an ISA slotted, C3-compatible motherboard for any good SB support. Well, I suppose I could sell my Apple PC Compatibility cards to get the funds. At least last I looked the SB16s commanded a large price... I don't want to think about Voodoo prices, haha.

So if I'm going to go down this route, which of the motherboards from that wiki list would be the most obtainable and still have at least one ISA slot?

Where are you located? Options and costs can vary widely.

What I'd do in your shoes is take that list and just check the local version of Craigslist every evening and look to see if one pops up in an acceptable state for an acceptable price.

Note that that list was made back in the day by Via itself looking at then new boards. A lot of older boards could also support it, and would make the ISA requirement easier. Here's a Vogons topic to illustrate that:
VIA C3 Nehemiah vs. Coppermine(-128) and Tualatin

He's running a C3 on an Azza PT-6IBT, a bog-standard i440BX AT board - but not very common, however later in the thread Gerwin posts this list which contains some classic - and common boards:

Working fine at 9.0x133=1200MHz, Quake 1 in 640x480 gives about 70 FPS on all these boards (write combining enabled), Speedsys g […]
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Working fine at 9.0x133=1200MHz, Quake 1 in 640x480 gives about 70 FPS on all these boards (write combining enabled), Speedsys gives +-800 points:
i440BX Slot 1 Gigabyte GA-6BXC Rev 2.0 - MS6905 Master v2.3 Slotket or Slot-T, Powerleap BIOS Award 6.00PG.
i440BX Slot 1 SOYO 6BA+III - MS6905 Master v2.3 Slotket, BIOS BA+III_2BA6.
i440BX Slot 1 Asus P2B v1.04 - (With VRM upgrade) MS6905 Master v2.3 Slotket, BIOS 1014 Beta 003 with ROM.by Tualatin patch.
i440BX Slot 1 Aopen AX6BC v1.4 - MS6905 Master v2.3 Slotket, BIOS R2.59.
Apollo133A S370 Chaintech CT6AJA4 - IIRC with Lin-Lin adapter.

Did not work:
i440BX Slot 1 Shuttle HOT-661 v1.1 - (With VRM upgrade) MS6905 Master v2.3 Slotket, Got only up to VIA C3 Samuel 2 running, this is not a BIOS limitation.
i440BX Slot 1 Intel SR440BX - MS6905 Master v2.3 Slotket, None of the C3 CPUs can boot, probably a BIOS restriction.

Asus' P2B is arguably the best all-round Slot 1 retro board out there, at least if you have a late revision with a good VRM. GA-6BXC amd AX6BC are also solid and more importantly for you common boards with ISA and great flexibility/performance.