Re: Apple //c+ questions....

[supertimer@aol.com (Supertimer)]

Rubywand <rubywand@swbell.net> wrote:

>Nick writes ...
>> 
>> A IIgs should be able to go faster than a IIc+, no matter what...  It has a
16bit
>> data path, where the IIc+ has only 8, so mhz for mhz it will be twice as
fast.
>> (Yeah yeah... I know, because the numbers say it is twice as wide doesn't
mean it
>> is twice as fast, but the basic architecture is similar, so by
approximation...)
>> 
> ....
>
>     Except that the 65C816 connection to the Data bus is also 8 bits. Given
the
>same software-- for example, a BASIC program-- a IIc+ will be somewhat faster
than a
>stock IIgs.

True about the data bus, but the data bus is not everything.  The IIGS has
a 24-bit address bus, which means the CPU can directly address 16MB of
memory.  Any software going through trying to access more than 64k
is going to suffer a huge speed penalty because of the need to bank
switch and considering most IIe/IIc software uses 128k, the IIGS has a
huge speed advantage, even over the IIc+'s faster Mhz.  The IIc+'s
CPU must jump through hoops to access more than 64k.  The IIGS CPU
has 16MB of space to play with without the need for such acrobatics.
Second, the IIGS CPU is 16-bits internally, so it can handle computations
more efficiently.  That's another speed plus.  If you compare 8-bit
software, then the IIc+ may be faster.  But if you try to write a program
from scratch, one using 65C02 code and one using 65C816 code and
run them on the IIc+ and the IIGS respectively and both are trying to
do the same task, the IIGS would probably come out ahead, especially
if a lot of memory is required.