I need to find my 286 boards again, they are in a box somewhere.
I have a super fast 286 board with an Intel 286 12 MHz. I also have a 48 MHz crystal to replace the 24 MHz one and a Harris 25 MHz CPU, I have just not mated the three yet.
Im pretty sure this combination will be really really fast at 24 MHz if everything works out, with luck even fast enough to rival some members Harris 286 overclocks at ~30 MHz. The BIOS lets you change pretty much every timing there is but defaults to pretty slow settings with the ISA bus running at half the CPU speed. I think replacing the CPU and doubling the speed with a 48 MHz crystal should be more or less hassle free.
The question is how agressive settings I can use when everything is running at twice the speed. With the 12 MHz CPU I can set every timing and other setting to the fastest value and run the ISA bus in sync with the CPU.
My plan B is a PC Chips M209 motherboard that uses a Harris 20 MHz CPU at the moment. This board would probably do close to 30 MHz but I'm pretty sure the other board will be faster even at 24 MHz.
I also have an Intel 287XL I orderd from China a week ago incoming. Not the fastest 287 CPU clock for clock but at least they can handle high clocks should some motherboard try to run it in sync with the CPU.
New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.