Re: Chips & Processors & Oscillators and other Go Fast Goodies?

[Wayne Stewart <waynes@intergate.bc.ca>]

Marvin Miller wrote:

> Hi Wayne, Greg & Ruby;
>
> As greg mentioned, it's a 7MHz/32K ZipGsx 1.02 card.
>
> With regards to the speed of the memory chips, my experience has
> always been that the best way to fly is identical (matched) memory
> running at the lowest nanosecond rating. Are you saying that there is
> a limitation elsewhere in the card that causes it to not take
> advantage of faster memory? As far as cooling goes, I'm not too
> worried, I have lots of little fans all over the place for my 'Quest
> for Speed' !
>
> The issue about memory speed versus cache speed was brought up because
> I seem to remember a post about the speeds being important, not the
> size, betweeen the cache and the main memory.

There's no correlation between cache speed and ram speed.
Your memory card is accessed at a set speed and once you have fast
enough RAM anything more is a waste.

> I'd really prefer to dig up some of the wide chips if possible. I
> don't really want to modify the card in any way other than plug in's
> if possible. So, I guess the questions come back to;

To go over about 12mhz you'll likely have to modify the card.
Usually you need to replace the 74F02 with a 74HCT02 to get
over 12mhz and it's soldered in.

> Does anyone have a new chip for me?

> Is there another limitation on memory speed other than the chip's
> actual NS rating that would negate the benefits of faster memory?

The card and computer's buss speed place the limit on how fast the
chips are accessed. As long as the chip can keep up with the card
and computer anything extra does nothing.
Not directly applicable but a very good example of slow memory
cards are any of the regular slot RAMcards such as the RAMfactor.
I've had anywhere from 250ns to 70ns chips in them and they still
operat dead slow, in fact I can access my hard drive faster.

> The Oscillator I have is rectangular - so it sounds like our
> electronics shop should be able to get them. I'll check out the FAQ's
> that Ruby mentioned and see what comes up from there as well.
>
> BTW; With regards to these mods, I just want the fastest & tightest
> //GS possible. I'd like to see 20Mhz or higher if possible. My
> thinking was that memory quality & speed would also be a potential
> issue at higher speeds. To me, it's kind of in keeping with having the
> fastest machine around, especially including Vancouver ;-))

Unfortunately the card tops out at about 16mhz in the best of cases.
When upgrading an accellerator a lot depends on that specific card
and computer. Some top out at 12mhz and some can be made to go
faster.

    Wayne