Date   : Wed, 14 Apr 2004 19:26:19
From   : Sprow <info@...>
Subject: Re: OVERCLOCKING

In article <Marcel-1.53-0414155606-b49xSBG@...>,
   Johan Heuseveldt <johan@...> wrote:

> Normally I would say that it is not possible.
> But I thought I should wait a few days.! :-)
>
> > I recall that the Solidisk 4Meg board did this. I think it had it's own
> > faster memory, as well as a fast 6502 CPU.
>
> So there is no real overclocking then

Don't get too fixated on the Soldisk board. Mike Cook (I think) did an
article on overclocking the main board. In summary:
 - faster CPU
 - faster 1MHz varients of 1MHz parts (eg.6522A rather than 6522)
 - change PCB links to run 1MHz parts at 2MHz

> > Things you need to bear in mind are:
> > * The on-board RAM won't run faster than 2Mhz
>
> Actually it already runs on 4 MHz for the normal 2MHz machine, but no doubt
> you know that, trying to ease the explanation. :-)

I always thought it to be 2MHz RAM, just that the video and CPU accessed it
on opposite phases of the clock.

Anyway, problem with 2MHz VIA would be that "TIME" would increment at the
wrong speed unless the MOS ROM was tweaked to load the timer with 1996
instead of 998,
Sprow.