[WBEL-users] RAM

[Namdar Bolour]

William Hooper wrote:

>Mário Gamito said:
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>>Hi,
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>>I have at work for desktop a 1.7 GHz Celeron, with a 256 MB dimm at 333
>>MHz in one slot.
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>333MHz, as in DDR?
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>>Well, it happens the i have two dimms of 64 MB each at 100 MHz.
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>100MHz as in plain old SDRAM?
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>>If i add them to the machine, (making a total of 384 MB) will i gain or
>>loose in the overall performance (because of the bus speed difference?)
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>If the above is true then the old RAM won't fit in the motherboard.
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Willaim Hooper is probably right in his guesses.  That is, if the
existing RAM is 333 MHz, then it is DDR, not plain old SDRAM, since
plain old SDRAM does not run that fast.  (When they say 333 for DDR, the
clock is actually running at 166 MHz, but two words are transferred with
each cycle, so it's effectively 333 - thus the term Double Data Rate.)
Therefore, your plain 100 MHz 64MB modules will not fit, because DDR RAM
modules have 184 pins, while plain old SDRAM modules have 168, and DDR
is not backward compatible with SDRAM.

If it's any consolation, it probably would not make much difference in
performance, even if you did have a motherboard that would accept both
types of RAM.

-- Nam Bolour