Memory Question

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Simple question (I hope). My Mb supports both 400MHz-PC3200 and
333MHz-PC2700 memory.  I currently have 2 256 333MHz-PC2700 Dimms in place
on the mb, and I want to add a 512 in an empty socket for 1G total.  My
question is should I buy PC2700 to be compatible with the memory already in
place, or should I buy PC3200 memory because it's faster, or is either one



Re: Memory Question

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Either should be fine. The job of the BIOS, is to find the best
combination of settings, that won't exceed the specs of any
individual stick. Since you have two DDR333 already in there,
the BIOS should be running at DDR333 already, and should continue
to use that setting if a third stick at DDR400 shows up.

Note that some motherboards have restrictions on speed versus number
of sticks of memory. Memory bus loading affects the electrical
signals and is responsible for the restriction. On the newer
motherboards, there are a few memory divider ratios (ability
to run memory and FSB at different frequencies), where this
is not a problem. There are some chipsets, where a particular
FSB choice also fixes the memory speed choice. The issue in
this case, is adding memory, could cause the BIOS to set the
memory a notch lower than before, which might also impact the
CPU operating speed. Have a good look at your motherboard manual,
or do a Google search, to see if there is any chance of that
happening with your motherboard.

You could replace the memory with 2x512 or 1GB. You could buy
512MB now, and test it. If there are problems, you could purchase
a second 512MB, and put the 2x512MB in slots 1 and 3 (best for
a three slot single channel motherboard). Alternately, you
could buy a 1GB stick and use it alone. But the 1GB solution
that doesn't allow an incremental testing strategy, like buying
one at a time of the 2x512MB solution.

For testing, use memtest86+ from . Start by testing
the current RAM in the computer, to see if it is still good. The
test results may suggest a different answer to your purchase.
Two passes of memtest86+ testing, if error free, is enough, as
memtest86+ doesn't catch all problems - but it is a good test
if there is a "bad spot" in the memory, and I've caught problems
in a couple sets of cheap sticks with it. Prime95 torture test
option ( is a better test of processor and memory,
although Prime95 doesn't test the entire memory the way that
memtest86+ can.


Re: Memory Question

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Memtest can't test ALL the ram either. The program itself takes up some
ram, and some is stolen by hardware (integrated video) and can't be
tested at all.

Re: Memory Question

The PC3200 RAM would only run at the speed of the slowest other sticks:


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