Re: TransWarp & Zip GS upgrades

[supertimer@aol.com (Supertimer)]

Phoenyx <quazar@dcnet2000.com> wrote:

>I would love to get into the buy program, I just can't afford it.
>If however, you decide to get ahold of the oscillators I would
>like one of them, about 40 mhz. It surely is tempting to boost my
>GS up to speeds which I see only in Kegs. However, if I can
>squeeze a little more out of it, I'll be happy.

Do you have a TWGS with the stock 7Mhz CPU?  If so,
a 40Mhz oscillator for 10Mhz operation might not be
possible.  The 7Mhz CPU was not very overclockable at
the standard 5v voltage (sounds high from a PC point of
view, doesn't it?  On the 65C816, that's normal voltage)
and tweaking the power supply to provide 5.2 to 5.5
volts is NOT fun.  I would suggest getting a 32Mhz
oscillator and, if you like, a 36Mhz one too.  The 7Mhz
CPU is practically always overclockable to 8Mhz with
the standard voltage.  9Mhz should work some on some
7Mhz 65C816.

The newer design 14Mhz 65C816 is different because
on the TWGS and Zip GS it is underclocked so it runs
very comfortably at 5v at any speed.  In fact, the design
has proven stable up to at least 20Mhz which is why
CMD can use them in the SuperCPU accelerator at
20Mhz all the time.  In fact, running the newer 65C816
at higher than normal voltages is a waste of time and
will put your entire IIGS at unnecessary risk.  That's
why I tried so hard to get Nathan to update his FAQ
on accelerators which recommends voltage increases.
At the time, Nathan ignored all requests to update the
FAQ.  I believe there are still folks out there who have
5.5v on the 14Mhz chip for no benefit at all because of
this.

What is really upsetting is that this flawed FAQ is still
recommended by some because of a misplaced sense
of loyalty to Nathan.  If some folks want to use it, then
at LEAST update the damn thing rather than put other
people's rare and valuable hardware at risk.

Note to newer readers of csa2: the current csa2 FAQ
on Apple IIGS accelerators is not the Nathan one, so
don't worry.  I'm talking about the one floating around
some web sites.