Archived from groups: alt.comp.periphs.mainboard.asus (More info?)
In article <Xns95323B327EB6Cspamspamityspam@126.96.36.199>, jimb
> I need to add more memory. Currently, I have 2 256 meg modules from
> Kingston, I think they're 3200. They're matched so I get the dual channel
> The users manual says that there are three slots. Can I buy a 1 gig dimm
> and drop in it the third slot? What should I watch for?
There are a lot of 1GB "stacked" DIMMs. Instead of 16 chips and a double
sided layout, they have 32 chips. There may be two chips packaged inside
one plastic body, so it can be hard to tell by looking. Another
method has the chips piggy-backed on one another. "Stacked" DIMMs
are hard for the memory controller to drive, because they have double
the recommended number of electrical loads.
If you go to Kingston or Crucial and use their DIMM database, you'll
get a "proper" 1GB DIMM, one with only 16 chips on it. The price will
be higher as a result. There are plenty of the cheaper stacked DIMMs
on the market, and the vendors of those products are not always
honest about how they are constructed. In a case like this, perhaps
a local vendor, who is within reach of whatever trade laws apply in
your country, would be another way to do such a purchase.
Also, I had a look on the Mushkin web site, and they have a Mainboard
Qualification web page. This is what it says for A7N8X:
"Unlike the original nForce 420 or 415, the nForce 2 does not
take any performance hit with a single DIMM as opposed to two
DIMMs, however, running 1GB unbuffered DIMMs, the performance
dropped by approximately 50% which may be caused by the specific
addressing scheme of the chipset. Please note that this performance
hit occurs only with actual 1GB modules, not two 512MB modules
used together for a total of 1GB. 512MB modules work perfectly and
do not cause performance loss."
Now, if that is true, maybe your best configuration would be 2x256
on one channel, and 512MB on the other channel (slot3). Buying a 512MB
involves no risk, because economically it doesn't make sense to stray
from the 16 chip, double sided configuration, so you are more likely
to get something that will work.
If you need even more memory, then 3x512 would be a way to get it, or
go with 2x256 + 1x1024 like you planned, only buy the 1G module from
Kingston or Crucial. And, if Mushkin is right, that last config will
be the slowest solution. 2x256 + 1x512 will be as fast as you can
get it (i.e. then the limit is whether everything is CAS2 or not).