[comp.sys.apple2] speed of mac vs. speed of iigs

pat@pro-shop.cts.com (Pat Regan) (03/17/91)

i saw that a 33mhz 386 is about 40 times faster than an apple iigs.  how
much faster is a mac comparred to a iigs, or even a mac compared to a 33mhz
386.  or maybe even compared to a slow 486?

pat
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gwyn@smoke.brl.mil (Doug Gwyn) (03/17/91)

In article <8053@crash.cts.com> pat@pro-shop.cts.com (Pat Regan) writes:
>i saw that a 33mhz 386 is about 40 times faster than an apple iigs.  how
>much faster is a mac comparred to a iigs, or even a mac compared to a 33mhz
>386.  or maybe even compared to a slow 486?

Such speed comparisons are overly simplistic; actual speed of operation
depends very much on the application.  For the kinds of applications that
I use, there is NOT a factor of 40 discrepancy in speed.  (I have used
both a 33MHz 386 and my IIGS.)  The best C compilers for the 386 seem to
generate better code than the available IIGS C compilers, which has an
impact for applications written in C.  Processor speed of the 33MHz 386
runs around 3 times that of a TWGS-equipped IIGS, for comparable
applications coded in assembly language.  The 486 processor is roughly
twice as fast as a 386 using the same clock rate; 25MHz 486s are the best
that are currently available, and can be expected to compute about 5
times faster than the TWGS.  Floating-point speeds are dramatically
affected by the use of hardware FPUs; the 68881 in the Innovative Systems
FPE for the IIGS is pretty good, if the application uses it directly
rather than via the SANE tools.  However, as a II bus peripheral there is
an inherent bottleneck in accessing the FPE that makes this slower than a
comparable IBM PC/AT clone setup with an 80387 or comparable coprocessor.

The problem with comparing desktop-oriented systems such as the IIGS or
Mac against IBM PC/AT clones is that the latter often have been used in
the generally cruftier text-screen mode, which is inherently faster.
A good comparison should use Windows 3.0 in extended mode on the PC/AT
clone.  (By the way, that is a much nicer environment than the IIGS
Finder; I haven't used the Mac MultiFinder enough to know how it
compares.)  Bitmap graphics operations take a lot of CPU cycles, and
the use of color makes it much worse.