Re: Plug a 14Mhz 65816 into the Processor slot....what happens?

[Rubywand <rubywand@swbell.net>]

tws writes ...
> 
> What would happen if you replaced the processor in a IIgs with a high
> speed 65816?
> 
> Any speed increase at all?


     The rated speed indicates how fast the uP (microprocessor) can go.
The current standard WDC 65C816's are rated at 14MHz but generally test
okay up to around 16MHz.

     Actual operating speed depends upon the clock frequency. That is,
the oscillator signal you feed into the uP clock pin(s) determines how
fast things happen in the uP chip. So, just swapping in a 14MHz 65C816
will not change GS speed because the clock oscillator signal will tell
it to run at the same speed as the old 65C816.

     So, could you plug in the faster uP, cut the old clock ("Phase 2
in") line, and connect a 15MHz osc module to clock the uP at 15MHz? Yes;
but, you would find that several important sub-system IC's would not be
able to deal with the uP at such a high speed.

     Another problem would be that uP speed would be fixed at the speed
set by its osc module connection and could no longer be slowed to act
like an old Apple II.


     There are lots of things which block on-motherboard improvements
like more speed and more RAM on the GS. Most of these relate to the mess
created by requiring old-Apple2 compatibility. Others relate to RAM and
sub-system controllers which would be too slow whether or not anyone
cared about old-Apple2 functioning.

     So far, the best way to increase GS speed is to use an accelerator
board.

     

 
Rubywand