Re: New chip in TWGS (sources for oscillators)

[supertimer@aol.com (Supertimer)]

cornelio@san.rr.com (L. Cornelio) wrote:

>supertimer@aol.com (Supertimer) wrote:
>
>>If not, I suggest getting the 50Mhz and 40Mhz units.
>>12.5Mhz TWGS (50Mhz oscillator) almost always
>>works, but with a 40Mhz unit, you can fall back on
>>10Mhz operation if necessary.
>
>FYI, my ZipGSX works fine w/ a 40 mhz & no chip swap.
>Does that maybe imply that w/ a chip sway 50 or even 60 will work?

Very likely yes.  Especially the 50.  What was the Zip
clocked at before?  If you have the 8Mhz processor of
the Sanyo design, you have a very overclockable chip.
It does not hurt to give it a try.

>I was wondering which cards were considered more
>"easily upgradeable" the TWGS or the Zip.....

It depends.  TWGS is simpler to upgrade all other
things considered.  It has cache RAM fast enough
so that to upgrade it usually involves changing only
the oscillator and the CPU.  For minor speed
upgrades, sometimes only the oscillator needs to
be replaced.

But the TWGS is older.  It came with either 6Mhz
or 7Mhz CPUs of the older design.  The 6Mhz
version was not very overclockable.  Thus, for
major speed upgrades you need a new CPU for
the TWGS.

The Zip GS started with CPU chips of the type used
in the TWGS, but the Zip GS survived long enough
that they started using the Sanyo versions of the
chips.  These came in either 8Mhz or 14Mhz
versions.  These were VERY overclockable.  Some
people have pushed the 8Mhz chip to 15Mhz, for
example.  So if you have the "good" 8Mhz chip,
you can often avoid a new CPU and thus save a
step compared to the TWGS.

BUT if your Zip GS started out with the older
7Mhz CPU of the non-Sanyo design, it is usually
harder to upgrade than a TWGS.  That's because
7Mhz Zips came with slow cache RAM chips.
So on older 7Mhz units, the cache RAM chips
often needed to be replaced.  This is difficult
because fast cache chips are now available only
in the 300 mil packages.  Zip GS uses 600 mil
ones.  Thus adapter sockets must be used.
These are rather expensive ($7 each).  It is
either that or solder a new row of socket pins
for each cache RAM chip to plug into.