On 30 Mar, 11:07, Paul <nos...@needed.com> wrote:
> ToolPackinMama wrote:
> > Paul wrote:
>
> >> I'm really surprised the user manual for the computer, doesn't say
> >> a few words about the memory
>
> > Ditto. BTW, Paul, thanks for a useful post.
>
> Doing a little checking, as near as I can tell, the T180 has a
> Sempron processor, and is likely socket AM2.

It is AMD Sempron 3200 http://www.ebuyer.com/UK/product/123118

acer-euro.com wrote that Acer Aspire T180 takes DDR2-533 memory.

While on Kingston.com it says DDR2-800.
http://www.ec.kingston.com/ecom/conf...submit1=Search

And curcial.co.uk says that it takes any of DDR2 PC2-4200,DDR2
PC2-5300,DDR2 PC2-6400,DDR2 PC2-8000.
http://www.crucial.com/uk/store/list...el=Aspire+T180

I have asked acer-euro.com to elaborate on as to why DDR2-533 is most
suitable for the machine I have bought.


> The Acer site doesn't have a downloadable manual for the T180 yet,
> so I cannot look at that.
>
> The Sempron processor has the memory controller inside the processor.
> Which means the chipset used on the Acer motherboard is irrelevant
> to the behavior of the memory.
>
> If I try and track down the info on the AMD site, the 32559.pdf
> document "BIOS and Kernel Developers Guide" has some info on
> how the memory map corresponds to the chip select signals on the
> processor. What is missing though, is doc 31117.pdf, which would
> have given a pinout of the processor, and allowed figuring out
> what signals were actually available on the processor. That document
> is apparently only available under NDA, which is stupid seeing as
> previous S939 and S754 processors were downloadable.
>
> So the only other thing I have to go on, is an Asus M2NPV-VM motherboard
> manual. (I think M2NPV-VM uses the same chipset as the Acer T180, which
> is why I selected that manual.) That manual claims, for socket AM2, that
> the less strict matching rules apply.
>
> "Memory configurations
>
> You may install 256MB, 512MB, 1GB, and 2GB unbuffered ECC/non-ECC
> DDR2 DIMMs into the DIMM sockets.
>
> - For dual-channel configuration, the total size of memory module(s)
> installed per channel must be the same (DIMM_A1 + DIMM_A2 = DIMM_B1
> + DIMM_B2).
>
> - Always install DIMMs with the same CAS latency. For optimum
> compatibility, we recommend that you obtain memory modules from
> the same vendor.
>
> - Due to chipset resource allocation, the system may detect less than
> 8 GB system memory when you installed four 2GB DDR2 memory modules.
>
> - This motherboard does not support memory modules made up of
> 128Mbit chips or double sided memory modules using x16 chips."
>
> Now, of that information, I don't know if Sempron supports ECC or not,
> or Sempron supports 2GB modules. (TheCrucialsite lists max memory as
> 4GB, or 1GB per slot for the T180.) With the lack of info on the AMD site,
> it is pretty hard to verify that part. There is a good chance that the
> "less strict" matching rules mentioned above, would still apply to
> Sempron.
>
> I don't know what to make of the suggestion that the modules should have
> the same CAS latency. The BIOS should just use the slowest timing of
> the lot.
>
> So, if you currently own 512MB, you could buy another 512MB module so
> both channels have the same amount of memory. If you wanted even more
> memory, you could purchase 2 x 1GB more memory, for a total of 3GB.
> You would install 512MB + 1GB on one channel and 512MB + 1GB on the other
> channel, and as long as the total memory was the same, chances
> are it would still work in dual channel mode.
>
> If the new 512MB module you purchased, had the same number of chips as
> the original one, I would think, so much the better.
>
> If it was my machine, I'd probably just pull the 512MB stick, and
> install 2 x 1GB. And not bother buying a matching stick for the
> existing 512MB one. I guess it all depends on how much money you
> have to spend on this project, as to whether you go with 2x512MB,
> 2x1GB, or (2x512 + 2x1GB). With an OS like Vista, more is better,
> at least according to this:
>
> http://www.anandtech.com/showdoc.aspx?i=2917&p=3
>
> Paul