Re: Can't go faster than 10MHZ on my IIGS

["Rodney Hester" <rod3@mindspring.com>]

"Dana Eckel" <deckel@info-link.net> wrote in message
news:5WTf7.45$xi.30563@news7.onvoy.net...
> Ok,
>    I have a Zip GS 1.02 with 32MHZ crystal, upgraded to 64K of Cache. My
> IIGS is a Rom 1 unit. I have tried 40 MHZ, 50MHZ, and 64MHZ crystals with
no
> success. Could my ram cache be bad? How do I know it is even seeing the
64K.
> I used skinny chips that are offed from Jameco and the adaptor from
> Digi-Key. And yes I also have a WDC-14 chip installed too.

I can almost guarantee that your data RAM is incompatible.  I've been
searching for "usable" data RAM for some time - 20ns tag RAM (skinny
w/adapter) works great, but I've yet to find data RAM I can push to 14MHz (I
can come close with wide 45ns RAM, but it's just not quite fast enough to
remain stable for long periods of time).

(If you haven't done the 74HC00 swap yet, now's also a good time to consider
that, if you want to climb above 12.5MHz.)

For those with stable, working data RAM (definition of stable and working:
you can run Twilight 2.0 with random modules for 24 hours without a hang,
crash, or dump to monitor) at 14MHz (or better), it would be very helpful to
all of us if you could tell us exactly what data RAM you're using that works
(manufacturer, speed, package, and any other pertinent information).  I
realize it's possible that even those same chips won't work reliably in
another Zip...but chances are, they will.  If we can put together an
"approved" (and even a "non-working") list, we'd be one step closer to
FAQing this puppy.  =)

Regards,
Rodney