DDR2 ?

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Being a bit behind the times...
I am only now getting around to building a machine with DDR2 RAM (parts
should be here Monday)

I have 4 gigs of DDR2 6400 coming.

Then today, I got a repair job for a 1 or 2 year old Dell machine that
badly needs a memory upgrade...it only came with 256 megs .

To save time I was thinking about installing the RAM that I already have
  coming but am not sure if it will be compatible since the machine only
has DDR2 3200.

I will of course remove the original RAM but will the 3200 work...even
at reduced speed, or should I just order some 3200 ?

Re: DDR2 ?

philo wrote:
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It's pretty funny. I checked on Newegg, and they still sell
PC2-3200 memory. A 512MB stick is $8.99 :-)

If you download a 128Mx8 memory chip datasheet (the kind that
would be used to make a 2GB DDR2 DIMM) -

http://download.micron.com/pdf/datasheets/dram/ddr2/1GbDDR2.pdf (9MB - see pg

the RAM ranges in speed grades from DDR2-1066 (1.87ns) to DDR2-400 (5.0ns).
The memory shows the maximum clock period for any memory product ranging
between those two extremes, as 8.0ns. And that means the fast memory
can run to a speed below DDR2-400 if desired. So, yes, your DDR2-800
module should be able to run DDR2-400 speeds.

A couple things are unclear to me. An additional ODT value was
added at some point, to faster RAM. I expect the code point would
be one that was reserved previously, so should be transparent (i.e.
the slow computer won't try to use it). One issue might be the
"tuning" of the BIOS may not be set optimally for 2GB modules. I've
had trouble running 2GB sticks on my crappy motherboard, and it isn't
the clock rate that upsets the DIMMs (they're running DDR2-533).
I suspect setup/hold time or some issue like that. Rather than the
clock rate itself being the issue. The BIOS must have the intelligence
to recognize a need for different settings, as a function of density/tech

Just stick it in and try it. It won't take too much testing to determine
whether it'll work. The BIOS is one of the variables here.

If you run the computer through the Kingston or Crucial sites,
what max ram quantity do they say the computer supports ?


Re: DDR2 ?

Paul wrote:
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Like an idiot
I, of course did not write down the model number...
So when the RAM comes on Monday I'll just give it a try...
if it does not work, I'll just order some DDR2 -400

I at least got the machine tweaked enough so it will operate again.

Amazing that a new XP machine would just come with 256 megs of RAM...
for win98 that would have been fine <G>

Re: DDR2 ?

Somewhere on teh intarwebs philo wrote:


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For a couple years nearly all entry and mid-level machines running XP *did*
come with 256MB.

"Build a man a fire, and he`ll be warm for a day. Set a man on fire, and
he`ll be warm for the rest of his life." Terry Pratchett, Jingo.

Re: DDR2 ?

Hi Philo...
I just upgraded a DELL Dimension 8200 with 2GHz CPU that only had 256Mb
of RAM. It appears that if you are dealing with either a DELL 8100 or
8200 series, the RAM used is a specific PC 800-40 RDRAM type and you
cannot use any other types. Furthermore, there are 4 RAM slots on the
mobo, and pairs of RAM slots must have matching pairs of RAM
installed...and any pair of unused slots must have a "dummy" CRIMM [a
special memory board with no RAM mounted on it] module installed.

Re: DDR2 ?

John the WebTV Man wrote:
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First off, I am was not talking about RDRAM

I have set up a few of those machines and that RAM is expensive!!!

It was DDR2   ($20 for 2 gigs  cheap)

Anyway, even though the original RAM was 400 mhz

when I put in the 800 mhz RAM it worked flawlessly...

the machine was not capable of clocking it past 533mhz but that's no big

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