I have a 386 that was upgraded to a 486. The original spec was cyrix 386 sx25 upgraded using a clip on cyrix 486 srx 50.

I have a spare math processor slot.

Does the bus speed have to match on the co-processor (i.e I am assuming the speed should be multiples of 25) and I may have read somewhere that the speed has to be equal or higher than the processor i.e should be 50mhz?

As the motherboard is 386 but upgraded to a 486, will there be any problems in using the 387 co processor. This is what I am thinking about but think the pricing is a but high.

http://www.ebay.co.uk/itm/US83S87-S...631?pt=LH_DefaultDomain_0&hash=item5ae5d3c4ff

Another question I have is can I use a video card in addition on this computer (im thinking of an isa video card).

Any help much appreciated.