I used PC100 SDRAM on a 66Mhz bus for about 9 months last year without a
single problem.  (Abit BH6 Motherboard)  My guess is that it's not the
66Mhz Bus that's giving you the problems but the fact that you're trying to
mix two types if RAM.  Usually mixing different kinds of RAM will produce
bad results, this may even be the case when trying to mix the same type of
RAM from different manufacturers.

However, keep in mind that my motherboard is very likely newer than yours
and certainly has a different chipset.  The BX chipset on my board is
designed to be run at either 66MHz or 100Mhz FSB and will therefore not
balk at feeding it RAM that meets those specs.  Your system may not be so
keen to receive the PC100 SDRAM but I can't be certain.

Bottom line.  You can try installing the PC100 SDRAM only, and leaving out
the 66Mhz SDRAM, but there's no guarantee it will work and you won't see
any benefit, so return the PC100 SDRAM and buy RAM that matches the stick
you already have in the machine.  Even if you're happy with the 40MB you're
getting (which would be silly) it's not worth any unpredictable results
(like loss of data) that you might not yet have noticed.

Hope this helps,

Bill Nussbaumer

By the way, I'm confused by your less than 50% calculation.  40 is 62.5% of
64.  No biggie.

At 02:58 PM 1/11/00 -0500, you wrote:
>Dear listers,
>
>I've read some listings regarding the use of PC100 ram and the ability to use
>it in place of 66mhz ram and that there was no real difference.  There isn't
>much price difference between PC100 and sdram these days.  I thought I'd
>share an experience I had.
>
>P233mmx  32mb 168pin sdram (1 stick) 2.1 gig hd running Win95 sr2.
>
>I added a stick of 32b 168pin PC100 to the existing sdram stick.  Computer
>recognized ram total of 40 megs instead of 64megs.  After talking with
>several dealers they told me using PC100 on the 66mhz FSB will result in only
>50% of that ram being recognized.  In my case, less than 50% was recognized.
>
>Any thoughts?
>
>Kevin Nowicki
>

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