"tim harrison" said:
i've got 256mb pc3200 ddr in slot 1 and 256 in slot 2. can i put 512 in slot
3 to double my memory? the manual isn't clear to an idiot like
me...sigh...any help muchly appreciated...
In terms of the ability to add memory, any combination of memory
sizes is possible, up to the manual's stated limit of 3GB.
That would be 3x1GB dual sided memory, to reach that limit.
One thing you have to keep in mind, is the more banks of
memory installed on a shared memory bus, the harder it is
for the chipset to drive the load. When you install the
new memory, you should use memtest86+ from memtest.org to
test the memory.
If you find the memory throwing some errors, you may have to
turn the memory clock down.
If you had a FSB400 processor, it would be natural to run
the memory sync at DDR400. You would use PC3200 memory to
make that possible.
If you had a FSB333 processor (CPU clock = 166, doubled by
the FSB), then running the memory sync would be a DDR333
rate. Either a PC2700 or a PC3200 DIMM is fast enough to
support a DDR333 transfer rate.
When you start adding more DIMMs, the FSB400 case is likely
to be a problem. You would likely need to turn the memory
clock down so that the memory transfer rate was DDR333, in
order for the chipset to properly drive the addresses on
the memory bus.
If the processor was FSB333, and you were already using DDR333
transfer rate, you might get away with the proposed combination
of memory. Or, if the memory is kinda crusty (or the 256MB
modules were in fact double sided, instead of the single
sided type), you might even have to turn the transfer rate
down to DDR266 to get error free operation. Not all the
Asus motherboard manuals are as clear on this subject as
they should be, and some experimentation would be
required.
If this was my motherboard, I would go through the following
analysis.
1) Current modules 2x256MB and both modules are double sided ?
Buy 2x512MB double sided modules and place the old modules
in a drawer. Expect to run the new modules at DDR333 with
stability and perhaps DDR400 if you were extremely lucky.
2) Current modules 2x256MB and both modules are single sided ?
Buy 1x512MB double sided module and add to the existing two.
Expect to run the modules at DDR333 but probably not DDR400.
If you buy one of the rare 512MB single sided modules, there
would be a better chance of experimenting with DDR400,
if you had a FSB400 processor. But if you were going to do
that, I would go to (3) instead.
3) Another option for case (1) above, would be to purchase
a single 1GB double sided DIMM and replace the two existing
256MB modules. There are various kinds of 1GB modules and
I would recommend a module with (16) 64Mx8 chips on it.
The "good" modules are the more expensive ones here.
http://www.portatech.com/catalog/memory.asp?ID=285
While it may be tempting to buy the cheapest module,
consider that some day, you may move that 1GB module to
another motherboard, and that motherboard may need a better
quality DIMM. I don't really see much value for money in
those cheapest modules.
I've gone to this level of detail, to prepare you for the
possible outcomes from your upgrade. I hope this is not too
overwhelming. It is intended to show you that the three slot
memory bus can be "twitchy", and not every upgrade will go
smoothly. You could buy one 512MB module and test. If the single
module tests error free, and yet the 2x256+1x512 combo doesn't
test error free, then you could buy a second 512MB module
and try the 2x512MB combination (and leave the 256MB modules
in a drawer).
Post back how it turns out, so others can benefit from your
experience (i.e. prove me wrong
)
HTH,
Paul
