1. basic (old) games would work
2. FPU is only used is some applications (Autocad, Quattro Pro...) and even less games (Falcon 3.0). FPU runs 1/3 of the CPU speed (or 1/2 with pin hack). So 10MHz FPU is good for up to 16-20MHz CPU.

6. only the last of 286 chipsets make it really breathe (Headland HT12, VLSI...)
7. you can always change clock generators. If you have 12MHz, then oscillator is 24MHz, you could change it with faster - but not all cpu's OC nicely.

Matching the FPU to your 286 motherboard is actually not so simple. In the original IBM AT, the FPU would normally run at 2/3 the CPU speed. Many of the early clone 286 motherboards were also 2/3, but some of them were 1/2. Some have jumpers that let you change the divider, and some have empty oscillator sockets that let you run any speed FPU you want. Some have soldered oscillators that run your FPU at a fixed speed. What it really comes down to is that you have to read the motherboard manual. This can be especially important for later generations of 287 FPUs. The Intel 80287XL for example has a 3/2 multiplier, so when you plug it into an original 5170 AT motherboard it will run at 1:1 (not 2/3 speed). Let's say your 12MHz AT Turbo 286 clone sets the FPU to run at 1:1 (12MHz) by default, If you popped an Intel 80287XL in there it would run at 12MHz * (3/2) = 18MHz!!! which would be overclocking. As far as I know 287s from Cyrix, IIT and AMD also have the 3/2 multiplier.

So basically you need to read documentation for both your 286 motherboard AND 287 FPU to make sure everything is running in spec.

As this motherboard was available with a 20 MHz CPU it should be a late 286 board so the floppy controller and BIOS will probably work with a 1.44MB floppy drive and the IDE interface will probably support the standrad disks type 1 to 46 and with luck a user defined setting.

If the CPU is in a socket get a 20 MHz CPU and a 40 MHz crystal (or a 16 MHz CPU and overclock it to 20 MHz). If the CPU is soldered get a 32 MHz crystal and overclock the 12 MHz CPU to 16 MHz, it should™ work.

When it comes to DOS gaming the 286 is pretty much equal to the 386SX clock for clock.

cool, sound slike a fun thing to try 😀
I will post a picture of it tomorrow. I have two exact ones, thinking of trying them out a little. I will probably gift one to a friend.

I hope nobody has anything against reviving this old thread…
I have the same motherboard…
Stojke, have you managed to build something with these motherboards?

Answering to your questions (probably you already know most of the answers anyway):

1. YES! Even some of the pretty advanced games up to ~1993 will run well on this machine (ie. Falcon 3.0, Flight Simulator 4.0, shooters like Alien Breed etc)

2. In business software mostly. On my board there is AMD 287 FPU - P80C287-10 (which runs with 286 12 MHz CPU).

3. AT-IDE

4. 1,44MB

5. You solder a pin header to the SIMM module to turn it into SIPP. Solder on both sides for strenght (electrically it doesn't matter).

6. It is very stable. Good chipset. But you may have problems if you try to enable UMB memory (not that it matters much).

7. By replacing (desoldering CPU) and quartz - yes, but again... why would you want to do that?

HanJammer wrote:

I hope nobody has anything against reviving this old thread… I have the same motherboard… Stojke, have you managed to build som […]
Show full quote

I hope nobody has anything against reviving this old thread…
I have the same motherboard…
Stojke, have you managed to build something with these motherboards?

Answering to your questions (probably you already know most of the answers anyway):

1. YES! Even some of the pretty advanced games up to ~1993 will run well on this machine (ie. Falcon 3.0, Flight Simulator 4.0, shooters like Alien Breed etc)

2. In business software mostly. On my board there is AMD 287 FPU - P80C287-10 (which runs with 286 12 MHz CPU).

3. AT-IDE

4. 1,44MB

5. You solder a pin header to the SIMM module to turn it into SIPP. Solder on both sides for strenght (electrically it doesn't matter).

6. It is very stable. Good chipset. But you may have problems if you try to enable UMB memory (not that it matters much).

7. By replacing (desoldering CPU) and quartz - yes, but again... why would you want to do that?

I just bought another one of those. I really like how fast HT/12A based boards are, but SUNTAC has some special place in my heart.