@freemo I remember those days well. My first PC was an IBM clone, 286 a6 MHz, the processor was fast for the time. Not an Intel part, they had moved on to promoting the newer and higher profit 386 gen processors.
I also bought and installed the math coprocessor for my machine. Needed since I wanted to use AutoCAD, and it required it.
So I ordered a 287 Intel coprocessor. It was about $300 CAD at the time, early 1991 probably. Would be a lot more today with inflation accounted for, and I was worried of damaging it during installation.
Turns out it did not work. I don't remember exactly what the symptom was, but not good. I had a $300 part, bought mail order, and might be stuck with it. 😟
@design_RG Also that gold is sexy AF
@freemo Yeah, that chip is pretty.
I had to return mine, when it did not work. Ordered another Intel part. Same thing happened. 😲
After buying and returning two expensive add-on chips, I decided to go to the local store who built my computer, and place an order with them. They ordered an AMD part, and when installed, it had problems too.
Turns out the motherboard was running too fast for the coprocessor - the highest speed 286 Intel made was 12 MHz, I think, so their 80287 was designed to pair with that.
The store replaced the motherboard (lucky for me, as they would not even consider it if I hadn't bought the copro from them). And then the co processor worked.
The system was a 286-16 MHz, 40 Megabytes HDD, dual floppies, VGA monitor, etc. Cost me $2,000 on Christmas 1990.
Similar specs with an entry level 386 famiky processor were close to $3,000 then.
Here's a photo of an AMD 80287, notice that it is rated for 10 MHz on the branding ( the -10 part number).
@design_RG Oh shit autocad.. That shit trained my depth perception skills :)