On 7 Sep 99, at 10:10, Mendoza del Pino Cesar Daniel wrote:

> My PC (Celeron 466MHz Processor, 440BX Chipset, 66MHz x 7.0) is currently
> working with:
>
> One DIMM     -8     SDRAM (PC100, 64MB)
> and
> One DIMM     -10     I_DONT_KNOW_IF_SDRAM_OR_EDO (32MB)
> and
> The BIOS configured for 60ns RAM memory (olny options available are 50ns and
> 60ns)
>
> Will I have any problems? No problems so far...
> What does the -8 and the -10 exactly means? 8ns and 10ns?

  FPM (Fast Page Mode) and EDO (Extended Data Out) RAM timing measurements
are typically in the 110/80/60/50 ns range, with smaller times required for
raster busses.
  SDRAM (Synchronous DRAM) works differently, and so its speed ratings have
to be measured slightly differently -- typically in the 12/10/8/6 ns range.

Conclusion #1:
  Your 32MB DIMM is also SDRAM.

Conclusion #2:
  While theoretically 10ms SDRAM can be used at 100 MHz, this leaves no
safety margin.  SDRAM must be rated no slower than 8ns to be certified
"PC100" for use with 100 MHz bus.
  Therefore, your 32MB DIMM works fine on your 66MHz bus, but might not be
reliable if you were to shift to a 100 MHz bus setting.  [Of course, your
Celeron probably wouldn't either, but you might make such a change as part of
upgrading to a PIII at some point.]


David G

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