Scraphoarder posted about these recently. IBM 03N2499 motherboard, I have one which I removed from an IBM Intellistation M Pro Type 6889. These are old high dollar EATX workstation boards with nonstandard front panel wiring so they're a tough sell to somebody without the original chassis. They're also a tough sell to somebody who -does- have the original chassis because those people probably already have working boards. Liquidators might let you have them for not much more than the cost of shipping (which may be considerable in itself though).
The motherboard and case are EATX with standard mounting points. For whatever reason it seems to be a standard feature of EATX boards in that time period to have that piece cut out in the corner. I even have a generic EATX case from back then which requires that cutout for boards to fit.
It uses a normal ATX power supply. There's an additional 6pin ("half AT" or whatever) aux power connector but it ran for years without that plugged in, and that was with dual Katmais and full load of RAM installed. I don't know how it's connected electrically, maybe it's providing extra power for expansion cards.
Dual slot-1, 440BX chipset
4x PC100 SDRAM sockets, max 1GB using 4x 256MB Registered ECC. Unbuffered memory supported but I don't remember if it limits how much you can install.
1 AGP, 5 PCI, 1 ISA (the extension on one of the PCI slots can be ignored, it's for a particular RAID card)
Intel 82558 10/100 ethernet
Crystal CS4235 sound (no idea how this behaves in DOS, but you have an ISA slot anyway)
Adaptec AIC-7895H onboard SCSI
National Semiconductor chip marked "VS9912AB SI163090 PC97307-IBX/VUL (don't know what it is)
Caps: Sanyo OS-Con at CPU Vcore (extremely reliable) and Nichicon PL at the VRM input (ditto). Tantalums all over the board - very reliable for a board that's being used, but if the board sits for years then the tantalums could blow when repowered.
BIOS flash chip is a surface mounted TSOP. Don't plan on ever being able to replace it.
check this out - these motherboards were made in the UK. Board markings declare that it's designed and copyrighted by IBM themselves.
CPU support - originally intended for Deschutes 100FSB Pentium 2s, but will run up to dual Katmai CPUs. The BIOS refuses to run with Coppermines. My board supported Coppermine voltages but when I tried using them, the BIOS displays an error message stating that the CPU is unsupported and refuses to boot any further.
With Katmais I remember the BIOS complained about not having a suitable microcode update, but they worked. I think there was a setting in the BIOS to skip the warning. To be honest I don't remember for certain if I ever fully updated the BIOS on this board, but I think I would have done that when trying to get the Coppermines to work.
The main problem with this board is that the front panel connector(s) is proprietary, as it usually is with OEM boards. I don't really blame the PC manufacturers for doing that because generic front panel connections suck, but I wish an improved connector had been standardized instead of every manufacturer doing it their own way.
When I swapped a modern ATX motherboard into the Intellistation case, I had to work out the pinout of the original connector on the case side. I think there might have been some info buried on the internet but I remember also probing some pins with a meter so I don't remember how thorough the internet info was. I figured out at least 2 if not all 3 LEDs and the power switch, but I don't remember about reset. The "adapter" I rigged up was held together with tape and looked ghetto but it worked fine. [As an aside, the other issue with that swap was that the original IBM case only has 6 expansion card cutouts, because that's what this board uses. If anybody reading this wants to adapt an ATX board into that case, be aware of this when picking what board to use.]
To adapt in the opposite direction, using this motherboard with a standard case's front panel connectors might be trickier because you wouldn't have the connector that fits the board socket(s). I'm looking at the board now and I see a 7pin which is marked "power", "HDD", and something like "LTAN" or "LIAN". I guess that's power switch and the HD/LAN LEDs, not sure about the power LED. The pins are the smaller, closer spaced type that you see sometimes on OEM boards, and would need that type of small connector to plug into them.
There's a nearby 4 pin marked "HF LED", whatever that is. Maybe that's 2 separate things.
There a 2 pin with an unusual style of connector which is chassis intrusion. Presumably those pins could be left open but I'm not sure if it's normally open or normally closed.
Summary: Quality is top notch, definitely better than typical retail boards, but the front panel issue and Katmai limitation kind of sucks. Lesser complaints are the lack of a replaceable BIOS chip and of course no support for overclocking. Requires an EATX case. In a pinch maybe you can just lay it on a table and figure out which 2 pins to short together as the power switch.
Personal Rating: 2/5 **
Quality is 5 star, but having to modify wiring to fit an ATX front panel is 1 star. Limitations as noted also make it less appealing to bother with for me. I guess I'll say 2 star, but if you don't mind the issues with integrating it into your system then you might score it way higher.