In article <(E-Mail Removed)>,
"SteveO" <(E-Mail Removed)> wrote:
> I built a PC with an Asus p4p800 mobo about two years ago. I put in 2
> sticks of Kingston ValueRam KVR400X64C25/256. I went with the
> Kensington PC3200 because it was on the approved chart for this board
> at the ASUS site.
>
> I'm trying to upgrade to 1gig. I can't remember if I just blop in 2
> more sticks of this stuff will it work ok with this mobo. I remember
> the p4p800 was pretty particular with the RAM you put in. Now I can't
> find that approved chart on the ASUS site.
>
> 3 Questions:
> 1. Will it work ok if I put 2 more sticks in of KVR400X64C25/256?
> 2. Where did that chart go??
> 3. I only have 4 slots on the mobo. If I add these 2 sticks, I'm done.
> Should I sell the 2 256MB sticks and but 2 512MBs?
>
> Thanks.
>
> SteveO
There is an Intel document here, that compares the performance
from various configurations of memory.
ftp://download.intel.com/design/chip...s/25303601.pdf
You could buy the 2x512MB, plug them into a pair of slots in
dual channel configuration, then run SuperPI and see how long
it takes to do a calculation. Then, plug in the 2x256MB extra,
and run the SuperPI test again. That will tell you whether
the extra 2x256MB makes any significant difference.
Two pairs of matched DIMMs (pairs of different sized DIMMs)
will be slightly slower than four matched DIMMs. The difference
is, if the DIMMs match in size (rows, columns, banks, ranks),
dynamic mode addressing is used. What that means, is a linear
set of memory addresses, are spread over the four DIMMs
uniformly, so that when a contiguous block of memory is fetched,
all four DIMMs take turns (as two pairs of course). That access
pattern, allows more memory pages to be kept open on average,
and an open page has a lower access time (less overhead, as
it doesn't need to be opened again). You may find the difference
is pretty small, between dynamic (interleaved) and linear
(non-interleaved) modes, and not worth worrying about.
You should also check Ebay, and see whether there is any interest
in 2x256MB DIMMs. The price they might fetch, might not be too
high (unless they were Winbond BH-5 chips or something).
HTH,
Paul