Re: Zip GS, 65816

[Wayne Stewart <waynes@intergate.bc.ca>]

> danaeckel@yahoo.com wrote:
>
> >I have a Rom 3 Apple II GS with a 8mhz zip GS card installed. I would
> >like to know where I can get a 20MHZ 65816 chip.
> >
> >Also, can I increase the cache on the Zip board?

The maximum cache on the ZipGS is 64k so if you have less than that
you can increase it.
The effectiveness of a cache increase is going to depend on how much
cache you have now. If you have 8k cache then an upgrade will have a
very noticeable effect on performance however if you have 32k then an
upgrade will only have a slight effect. .

If you haven't already I'd suggest reading the FAQ on Accelerators.
If you have a socketed oscillator it might be worth trying a faster
oscillator
by itself. If your cache is fast enough it's not unusual to see otherwise

stock cards running at 11 or 12 mhz.  If your cache isn't fast enough
then
this might be a good time to do something about it.

The ZipGS didn't usually need a faster 65C816. Usually the stock  8mhz
one
will work fine up to the limits of that card. If your card happened to be
fitted
with a 6 or 7 mhz processor the a faster one would definitely be needed.


When I first started upgrading my ZipGS I went to 10mhz by just changing
the oscillator. Then I got 12mhz by changing the oscillator and cache.
After that
I changing the74F02 and oscillator took me to 15.5 mhz. However my cache
was
too slow so it lacked stability so I chose to back down to 14.25 mhz. I
never did
bother getting around to picking up faster cache since at 14mhz you're
definitely
at the point of diminishing returns. However a bit later while ordering
something
else from altech I had them send me out a 14mhz 65C816.