Reply 40 of 123, by dionb
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- l33t++
GL1zdA wrote on 2020-03-06, 17:11:Given that the cheapest NuXT is $280, I don't see how you can make a new cheap 486 motherboard. If you can't get an existing 486 chipset, creating one from scratch in FPGA would probably be prohibitive and I don't think ao486 performance is what people are looking for when they build a 486:
https://www.youtube.com/watch?v=G32lGUVeodQ
Personally, I would buy only such board if it had performance comparable to the late 486 PCI boards. On the hardware side it would need at least several PCI and ISA slots, so micro-ATX is a no-go. 486 Baby-AT boards had often as much as 7 slots, including long VLB ones.
VLB is an interesting proposition. Are there still massive stocks of MCA connectors to use for that?
Not so convinced uATX is out of the question. That gives you four external slots. I/O will already be integrated on motherboard. Because PCI and ISA are mirrored you can share an external slot between them, so you could do 1x PCI and 4x ISA (+VLB if desired), or 2x PCI and 3x ISA.
What would you want to use?
- VGA? The design here integrates that. Not at all sure that's a great idea, but it certainly saves a slot.
- NIC? Yep, 1 ISA or PCI for that.
- Sound? Two ISA should be enough.
So you're only using three slots for a fully featured system, even assuming two sound cards (decadent). That leaves a slot for whatever else you want, like a discrete video adapter. I'd say the form factor is more than viable. Full ATX would limit choice of cases, increase costs & complexity significantly and forces you to go for a big-ass system.