Upgrading Computer Memory (DDR2-667)

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I have recently purchased a new Fujitsu-Siemens desktop computer. The
model name is SCALEO P-011. The price-to-feature ratio was very
impressive, and the my previous experience with this brand has been
nothing less than excellent.

However, one area where this PC is lacking is memory. It has only
512MB's of memory, and I would need at least 1GB. Unfortunately, I'm
very confused about what type of memory I should acquire. The
motherborad specification states the following:
* 4 DDRII DIMM memory slots (supports up to 4GB memory)
* Supports dual channel DDR II 667/533/400 DIMM
* Supports 1.8V DDR II DIMM

All was fine so far. I figured I should get myself a DDR2-667 1GB
memory kit. But when I went onling shopping for memory kits, I found
matters a little bit confusing. For example, Newegg.com has two
subcategories for DDR2-667 memory: PC5300, and PC5400. Furthermore, all
the gold, extreme, and whatever special edition memory kits are more
abundant in different categories. Like DDR2-800 or somesuch.

So, my questions are:
1. What's the difference between PC5300 and PC5400 DDR2 memory?
2. With the motherboard specifications I gave above, would the
motherboard be able to run memory modules of higer clock rates? For
example, DDR2-675,  DDR2-800, etc.
3. Could anyone suggest a decent memory kit what would work on my
configuration, and preferablly offered by Amazon.com?

Many thanks in advance.

Re: Upgrading Computer Memory (DDR2-667)

Quoted text here. Click to load it
go to www.crucial.com
Type in the computer details. you`ll be told what memory you can use.
Crucial are the experts.

Re: Upgrading Computer Memory (DDR2-667)

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Page 74, Table 40, lists the JEDEC approved speed grades (2MB doc):

DDR2-800 CL-tRCD-tRP = 4-4-4, 5-5-5, 6-6-6
DDR2-667             = 4-4-4, 5-5-5
DDR2-533             = 3-3-3, 4-4-4
DDR2-400             = 3-3-3, 4-4-4

There is no 675, so PC5300 versus PC5400 is "marketing". It has
a bit to do with "666" being the biblical "mark of the beast",
and 667 not being "different enough" from 666 for some people's
tastes. That would be my guess as to why there is a PC5400 RAM.

The lower the CL-tRCD-tRP in the above table, the faster the memory.
But we are talking small improvements here, and there is probably
no value in falling for the hype.

What combinations will work, really depends a lot on the BIOS
and the chipset. Some chipsets have the odd issue, like one
that won't run 4-4-4 at DDR2-667, and the BIOS makes it fall
back to DDR2-533. Your user manual is the first place to look,
for advice or restrictions on memory speed or timing. I cannot
find any info on your motherboard, so if you have a URL for
the user manual, or can tell us the chipset used, that would

Also, I don't understand what you are shopping for. You have
512MB of memory, which could be 2x256MB or 1x512MB. Are you
trying to find another 512MB module, so you have 2x512MB to
work with ? Or, are you buying 2x512MB to replace whatever RAM
is already in the machine. I take it you are aiming for a dual
channel configuration. If you are trying to match the memory,
more info about the memory itself would be needed. CPUZ
can dump some info about your hardware (cpuid.com) and
Everest Home Edition can tell you some things as well.
So, knowing the initial configuration, and its characteristics,
may play a part in the purchase decision. CPUZ can dump the
SPD information stored in the existing DIMM's SPD chip, for

(AFAIK, this is the last free version of Everest...)


Re: Upgrading Computer Memory (DDR2-667)


Thanks for your very valuable input.

I opened the case and took a look at the motherboard, and found it
labeled as "Gigabyte GA-8I945PE." I then searched Gigabyte's website
but they didn't have it listed anywhere. My guess is that it's
rebranded for use by Fujistu-Siemens. The closest match I found was the
GA-8I945P Pro motherboard.

I also failed to find an online version of the user's manual, but
here's the specs it had on the chipset and BIOS:
* Northbridge: Intel 945P Express chipset
* Southbridge: Intel ICH7
* Licensed AWARD BIOS, no further information given.

I apologize for being unclear on my exact requirements. As bought, the
PC has 512MB's in a 2x256MB configuration. I wish to replace the
existing memory with 1GB in 2x512MB configuration, so that I would have
room to upgrade to 2GB's in the future if needed.

By the way, I found it very funny that 666 would be considered a bad
operating frequency from a marketing point of view. Thanks for that
interesting bit of trivia :)

Re: Upgrading Computer Memory (DDR2-667)

m@abdulfatah.net wrote:

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My expectation for a 945 based motherboard, would be DDR2-667
would be the top speed offered in the BIOS, when using an
FSB1066 or FSB800 processor.

The advertising here, mentions both DDR2-533 and DDR2-667.


According to this Intel datasheet, DDR2-667 is supported on
945P and 945G, but not 945PL chipset. Page 24 shows what Intel
thinks is supported (and I wish I knew what "DDR2-667 4-4-4 in
Not supported" means from a practical standpoint):


There is a manual for the GA-8I945P Pro here:

I tried "Search by model" here:

"You searched for the Gigabyte  GA-8I945P Pro "

This is their suggestion of DDR2-675 (XM2S-5400UL) at 3-3-2-8 timing:

Now, what your motherboard does with this, really depends on whether
the FSC BIOS denies all attempts at adjusting or overclocking.
The CorsairMicro mentions DDR2-675 at 2.1 volts (while 1.8V is the
nominal value), so you would want some room to adjust Vdimm, to get
the most from the memory (i.e. turn up Vdimm, until memtest86+
runs error free). If the FSC provided BIOS complies with
the Intel intent, that DDR2-667 4-4-4 is not supported, it might
even pop you down to DDR2-533. Maybe someone else has a better
idea what would happen - a "vanilla" BIOS will start by reading
the SPD contents from the DIMM, as that contains the clock and
timing information. On an overclocker board, you could adjust
all the settings to the values intended by Corsairmicro, but
on an OEM motherboard, with an OEM-style BIOS, you may not have
the necessary controls to make such an adjustment, and might
just have to take whatever speed the BIOS ends up at.

You should search for articles like this, to see what advantage
you get from a higher memory speed. The memory bandwidth benchmark
went up by 28% in Sandra, and the PiFast benchmark improved
by maybe 5%.

http://www.viperlair.com/reviews/memory/other/mushkin/DDR2/pc4200 /

In this page, I see that moving from a CAS3 to a CAS4 memory
is not affecting the results too much.


So, here is the strategy:

1) If the motherboard offers the ability to set CAS, Tras, Trcd
   etc, and the memory clock, you may be able to override any
   restrictions placed on the memory timings the BIOS uses.
   You can buy a boutique memory DDR2-675 3-3-3 if you want,
   and if the BIOS starts it operating at DDR2-533, you can
   adjust it to its specified value. Having a Vdimm adjustment
   in the BIOS, allows extracting all the performance it has
   to offer. If you don't have a Vdimm adjustment, then the
   timing might have to be backed off a bit.

2) If the BIOS is one of those generic, fully auto, wonder
   BIOS, you have a potential problem on your hands. The
   Intel spec sheet says DDR2-667 4-4-4 not supported, and
   I get the impression that some BIOS run such memory at
   DDR2-533. If you buy DDR2-667 5-5-5 memory, then a
   dumb BIOS will stay at the 667 rate. Those two articles
   above suggest to me that clock rate is worth more than
   latency, so if you are faced with a totally dumb BIOS,
   then a cheaper 5-5-5 DDR2-667 DIMM, may automatically
   give you a more desirable result, than if the BIOS
   downclocks a more "elite" memory. The key to success
   would be that the SPD contains the magic 5-5-5 values.

Your job, is to examine the BIOS screens, take the
settings off "Auto", and see what kind of manual adjust
ments are available. If you have a good BIOS, you can
buy any DDR2-667 DIMM you want, to go with an FSB800 or
FSB1066 processor. The BIOS may start with a slower
setting, but with manual adjustment, you can get more
of what you paid for. But with OEM boards, my guess
would be you'll see a dumb BIOS, and buying a DIMM
that has "DDR2-667 5-5-5" timing stored in its SPD
chip, would be the best you could do for the setup.


Re: Upgrading Computer Memory (DDR2-667)

Hi Paul.

I can't thank you enough for the very valuable information you
provided. I'm by no means interested in over-clocking or other semilar
semi-conductor aerobics, so I opted to buy RAM with the exact same
specifications supported by the motherboard.

I took Someone's advice in one of the previous replies, and bought a
1GB memory kit from Crucial Technologies. It arrived by courier today
and I was able to install it with no problems. The motherboard
auto-detected the memory as DDR2-667, and Cpuz reports that it's
running in 5-5-5-15 timing, all of which are the exact same specs for
the memory kit.

Again, thank you for all your help.


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