On 9 Dec 1998 Walt Ezyk <[log in to unmask]> wrote:
>
>Hi everybody, I've got a 486DX-75 with an IBM 486 Blue Lightning System
>Board. I've got 8 megs of RAM and I'd like to increase my RAM to 16 megs.
>According to the manual I need two 4 meg SIMMS specified as 1MX36
>single density SIMM modules.

This sounds like the IBM Cobalt VL bus motherboard with a
soldered-on Blue Lightning processor with external maths co-pro.

If your goal is to upgrade the memory on this motherboard,
forget questions about 30 pin SIMMS.

You know the motherboard takes 1MX36 memory:
that's a 72 pin SIMM 4 bytes wide with parity.

You must have two of these on the board already, so I don't
understand why you translated that into 4Mx9 30 pin SIMM :-(

It also takes 4MX36, which is much better value for money,
so I would advise you shop for one 16MB parity 72pin FPM SIMM,
giving you a total of 24MB.

Your processor is clock-tripled so the bus is only running
at 25MHz and 80ns memory will work fine, but memory that slow
is rare these days, so there's usually no price penalty in
buying 70 or (better) 60ns which has more potential for re-use
on a faster motherboard.

(I've installed a Powerleap AMD5x86/133 on mine
which runs very happily at 160MHz, 40MHz bus.)

By the way, it _doesn't_ work with EDO, and 'double sided' 8MB
or 32MB SIMMS will at best only work as 4MB or 16MB.


Len Warner <[log in to unmask]> http://easyweb.easynet.co.uk/~len/ ICQ:10120933

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