21 Nov
2007
21 Nov
'07
12:57 a.m.
Doubtless the 386SX board designs were low-budged
also, which
probably figured into things. Some 286 vendors made a big thing of
the fact that a 286 could execute 16-bit real mode code substantially
faster than the 386SX. For example:
http://www.intersil.com/data/an/an121.pdf
On the other hand, the 386SX could execute 32-bit code. That is, if
you had any to run in 1989.
You do need to consider that that "application note" was a marketing
tool and the subroutines they designed for the application note of
course will make heavy use of instructions that are faster on a 286
than on a 386SX. On typical 16 bit code I didn't see a significant
difference on a cacheless 16MHz 286 and a cacheless 16MHz 386SX. I
don't currently own a 386SX machine, so I can't give current
benchmarks. ISTR that you could get a 386SX with an SRAM cache on the
motherboard. I don't recall that on any 286 boards, but I'm sure
someone else will point one out...
Eric