Path: utzoo!attcan!uunet!munnari.oz.au!metro!ipso!fawlty!johnmac
From: johnmac@fawlty.towers.oz (John MacLean)
Newsgroups: comp.sys.apple2
Subject: Faster IIGS
Message-ID: <517@fawlty.towers.oz>
Date: 28 Sep 90 00:07:19 GMT
Organization: Tower Technology, Lane Cove, NSW
Lines: 39

This may seem like a rather uninformed question:

In what area (eg: RAM speed, ROM speed, BUS speed, Timing problems) is the
actual restriction to just putting a new (faster) 65816 and new (faster)
clock into the motherboard of the GS, letting the FPI (Fast Processor
Interface) take care of slow downs?

In this way you would just get a N Mhz / 1 Mhz machine instead of the
2.8 Mhz / 1 Mhz machine. Where 2.8 > N > 7.

I believe that Transwarps come with 80ns RAMs and the average IIGS memory
card comes with 100ns - 150ns RAMs. This could be a problem, but the 100ns
RAMs could probably be accessed at 2 * 2.8 = 5.6 Mhz (just an uninformed guess).

The IIGS motherboard probably cuts down a high rate clock to produce the 2.8 Mhz
and the 1 Mhz signal from the same crystal. If this is true (again just a guess)
then replacing the crystal is not a good idea; but how much of a hardware hack
would be required to fix this?

Someone recently mentioned that the speed of the ROMs was a significant factor
when the GS was designed. Could the ROMs be easily copied into ROMs that had
faster access capacity (available today) (ignoring copyright issues - this is
a technical question)?

Would there be any problems with a faster (eg: 2 * 2.8 = 5.6 Mhz) GS
interfacing with the slow (1 Mhz) side of the system through the FPI?

Note that a 2 * 2.8 = 5.6 Mhz GS would probably be as fast as a 7 - 10 Mhz
Transwarped GS (because it would be a non-cached system).

Would someone with a bit more knowledge of the hardware than myself like to
answer / comment on / shoot holes in some of these issues.

John MacLean.
-- 
This net: johnmac@fawlty.towers.oz.au                   Phone: +61 2 427 2999
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Snail:    Tower Technology, Unit D 31-33 Sirius Rd,     Home:  +61 2 960 1453
          Lane Cove, NSW 2066, Australia.