On 1 Apr 99, at 8:52, David Nasser wrote:

> Wayne Ramlogan <[log in to unmask]> asked:
> >Is it possible to mix RAM; EDO and SDRAM PC100 or EDO and SDRAM
>
> I know of relatively few mainboards that support mixing simms, dimms.
> Maybe the new super 7 boards?

  The recent Socket 7 and Super 7 boards I've used support all three
types.  Mixing more than two on a single system, though, is probably
asking for trouble.

> My personal conjectures (somebody correct me if I'm wrong) are as
>   follows:
>
>   1.) Your edo is "rated" 60-70 nanoseconds.
>   2.) Your sdram is "rated" 6-10 nanoseconds.
>   3.) Your memory bus runs at one constant speed.
>   4.) This one constant speed with mixed mem. modules would have to
> approximate the speed of the slowest module.
>
> Hence you would be running sdram rated at 6-10 ns at something like
> 60-70 ns, a potential waste of resources. Fine for a short test period
> (if it works: I never take stuff like this for granted). Definitely not
> recommended in the long run.

  This might be true IFF the ns rating of SDRAM was measuring the exact
same thing as the ns rating of FPM and EDO does.  But if it did, it
would be wasteful to use SDRAM in a machine with an FSB any slower than
about 500 MHz or so; the fact that SDRAM is routinely used with FSB
speeds of 66-100 MHz makes it pretty clear that you cannot just compare
ns ratings across types this way.


David G

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