[comp.sys.ibm.pc] Is a 387 just a fast 287?

dmurdoch@watdcsu.waterloo.edu ( D. Murdoch - Statistics ) (10/02/88)

A couple of weeks ago I posted a question asking whether an 80386 system
using an 80287 would suffer substantially.  Thanks to everyone who
replied;  here's a summary of what I got.

Several people pointed out that the 387 is much faster than the 287, even
at the same clock speed, and since 16 and 20 MHz versions are available,
it ends up way ahead.  In my own experience, the difference wasn't that
great in a test I ran doing lots of multiplying and adding, but may be
for other operations.

A couple of people said that the 287 support built into the 386 is only 
temporary.  For example, the P9 or 386sx has dropped it.  This could mean that
386/287 combos will end up as strange beasts not supported by
future software.

Finally, one respondent told me that if a page fault occurs while running in
386 protected mode, the 287 can't handle it.

Thanks to everyone for replying!!

Duncan Murdoch