Nee help interpreting my DDR usage

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I used Everest to diagnose my system and I find the following under

 [ DIMM1: 1 GB PC3200 DDR SDRAM ]

    Memory Module Properties:
      Serial Number                                     None
      Module Size                                       1024 MB (2
ranks, 4 banks)
      Module Type                                       Unbuffered
      Memory Type                                       DDR SDRAM
      Memory Speed                                      PC3200 (200
      Module Width                                      64 bit
      Module Voltage                                    SSTL 2.5
      Error Detection Method                            None
      Refresh Rate                                      Reduced (7.8
us), Self-Refresh

Memory Timings:
      @ 200 MHz                                         3.0-3-3-8
      @ 166 MHz                                         2.5-3-3-7
      @ 133 MHz                                         2.0-2-2-6

Can someone give me a quick interpretation of the meaning of 'memory
timings'  and  '(2 ranks, 4 banks)' above?  I am running with one
1024MB DDR in a motherboard with two slots, one empty.



Re: Nee help interpreting my DDR usage

gecko wrote:
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The SPD chip (a tiny chip on the module) is the source of that info.
The three sets of timing values shown, correspond to the ability of
that PC3200 module, to run at slower speeds when necessary.

The two rank thing, is actually a good thing. That is, if the determination
is accurate, and we cannot know that for sure.

A rank is enough chips to make a 64 bit wide array. The memory bus
is 64 bits wide. For example, if I took eight 8 bit wide chips, that
would be enough to make a single rank. I might put those eight
chips on one side of the module, making it easy to add a second
rank to the other side of the module.

Since you've got a dual rank 1GB module, that means it is a low
density module, and can work with the vast majority of DDR
motherboards. There are some modules on Ebay, which use sixteen
of the 4 bit wide chips, and that is a single rank. Intel
chipset datasheets specifically exclude modules like that,
so at least Intel doesn't like them. I did discover, that
the JEDEC standard covers them, and yet the companies that
make those (bad) modules, never put their name on the module.
It is like they aren't that proud of their handiwork.

The "4 bank" is a specification at the chip level. There are
two BA signals, allowing up to four banks to be addressed inside
the chip. Each bank can have an open page, which makes it possible
for more efficient memory access (the transaction is shorter, if
the page is already open). From a consumer viewpoint, this is
largely irrelevant.

If you had a dual channel motherboard, you might try to match
the module characteristics if buying another. If the
motherboard is a single channel variety, then you could
do whatever you wanted. If you somehow managed to purchase
a slower module than your current one, the BIOS picks
slow enough settings, such that all modules can operate

PC3200 3-3-3-8 might be considered to be "industry standard"
memory. If you forked out more money, enthusiast memory
would be 2-2-2-6. The difference might be a few percentage
points in a memory intensive application. I bought the
2-2-2-6 type, purely so I could benchmark both situations.
(I can set my BIOS to 2-2-2-6 or 3-3-3-8 and see what
difference it makes.) My DDR system is in semi-retirement,
so it isn't that easy to run off a benchmark at the moment.


Re: Nee help interpreting my DDR usage

On Wed, 24 Dec 2008 07:29:38 -0500, gecko

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A followup question would be to what end do you need to
apply this information?  The memory you have looks like a
typical consumer grade 1GB PC3200 module.  If for example
you simply wanted to upgrade your memory, you should
probably buy another typical consumer grade 1GB PC3200
module to go along with it.

Re: Re: Nee help interpreting my DDR usage

Quoted text here. Click to load it

Oh I quite agree.  I just wanted to understand what I was reading.
Thanks and Merry Christmas.


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