Danny wrote:
>If your board can support FPM/EDO combinations I will have learned
something
>new. You may need to make changes to your BIOS settings if you are going to
>change from FPM to EDO. Rising edge vs falling edge, wait states for
>read/write,
>etc. From experience I have never came across a motherboard that can
>use a combination of FPM and EDO with no ill effects. The POST will show
that
>the SIMMS are installed but the board will not know how to utilize the
FPM/EDO
>combination. FPM and EDO use different timings and operate at different
speeds
>(ns). I believe that FPM uses RAS before CAS or vice versa. EDO uses among
>other things rising edge or falling edge, wait states for read/write, etc.

I have a Tyan Tomcat III that will accept banks of both. I can not mix
within a bank, say an 8 meg EDO simm with a 8 meg FP in bank zero, but I can
have two 8 meg EDO simms in bank zero and say two 8 meg FP in bank one with
no problem. I leave my BIOS RAM settings on auto and it adjusts itself
accordingly based on what type of simms are present. Another important note
is that being EDO or Fast Page does not explicitly determine the speed.
There is plenty of Fast Page RAM floating around out there that runs fine at
60ns which seems to be the standard speed of EDO.

I am not an expert on EDO RAM, but it is my understanding that EDO does not
have to be refreshed as often as Fast Page which means the processor is tied
up less. One of the primary reasons EDO is faster.

I'll also throw this into the discussion: I have and old P60 board that I
had before EDO was available and long before any P75's were on the market a
large number of which wouldn't accept EDO. The manual for the board makes no
mention of EDO RAM (probably because it didn't exist on the market yet).
But, this board will use EDO RAM with no problems that I can find. It isn't
that EDO is backwardly compatible (the issue that started this whole thread)
because my coworker's P75 won't accept them because it won't recognize EDO.
And, yes, they are confirmed EDO simms. Any thoughts on this?

--
Adam Gonsman
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