Please advise on P4C800-E Deluxe memory upgrade

  • Thread starter Thread starter Donald White
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D

Donald White

I have 2 P4C800-E Deluxe based systems I built 2 years ago. Each has
2x256MB for a memory configuration. I want to increase each to 1GB
total. Is there a preferred way to this from a performance perspective?

Is it better to replace the memory with 2x512MB? Or add 2x256MB to each
system? Or configure one as 2x512MB and the other as 4x256MB? I am
hoping that someone here can direct me to some data on the performance
of the memory subsystem with different configurations.

Thanks,

Don
 
Donald White said:
I have 2 P4C800-E Deluxe based systems I built 2 years ago. Each has
2x256MB for a memory configuration. I want to increase each to 1GB
total. Is there a preferred way to this from a performance perspective?

Is it better to replace the memory with 2x512MB? Or add 2x256MB to each
system? Or configure one as 2x512MB and the other as 4x256MB? I am
hoping that someone here can direct me to some data on the performance
of the memory subsystem with different configurations.

Thanks,

Don
Click to expand...

The executive summary, is the differences are trivial.

First, have a look at the Intel memory guide for 875.

ftp://download.intel.com/design/chipsets/applnots/25273001.pdf

Factors to consider:

1) Number of ranks (sides of memory) each config offers. More
is better, for dynamic mode interleave.
2) For overclocking, fewer sticks is better. (That is not
mentioned in the Intel doc. If you overclock the memory
enough above DDR400, you can gain more performance than
is lost if PAT is disabled.) If your 256MB modules were
single sided, it might not affect overclocking that much.
3) PAT reduces first cycle latency, and theoretically should
be applicable in any "synchronous" combo of FSB and memory
speed. Various claims are, it only applies at CAS2, works
at FSB800/DDR400, works for 2 sticks above DDR400, won't
work for 4 sticks above DDR400. Whether the number of ranks
of the sticks matter in the 4 sticks case, I don't recall.
(There are threads on Abxzone.com about PAT. It is the
BIOS design that decides all these things.)

In your situation, I would go 2x512 on one machine and
4x256 on the other. My assumption would be, the 256MB modules
are single rank (single sided), and rank-wise, 2x512 is the
same as 4x256. (You can buy single rank 512MB modules, but
they aren't really an economical format, and thus you won't
run into them if you are shopping by price. Normal 512MB
modules are made with 32Mx8 chips and are double rank.)

I would not invest in any more 256MB modules at this time.
They will have a limited resale value later. 512MB would
be slightly better, as they are the most common size. The
1GB modules being gobbled up for Athlon64 systems, are
too expensive if you are price sensitive - at least
good modules are. (Note that the cheapest form of 1GB
modules for sale, may not work well on many chipsets.
For example, look at the warnings on this product page,
for 1GB modules. Modules using 64Mx8 chips are the
"good" kind.)

http://www.portatech.com/catalog/memory.asp?ID=285

Paul
 
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