Boot memory problems.

Discussion in 'Computer Information' started by R. Giggs., Aug 15, 2012.

  1. R. Giggs.

    R. Giggs. Guest

    Ok I think I posted a long time ago about this but anyway.

    My computer was working fine but crashing in warm weather so I decided to
    the fan and heatsink, which I did. However when I put it back together I had
    problems, either nothing or beeps or whatever.

    I thought I might have damaged the CPU somehow, but then looked to memory as
    I had touched a stcik removing the CPU power cable.

    I eventually got it to boot properly with just one one gig stick in, it
    had a 256meg stick in as well but I can't add this 256 meg stick and get it
    boot properly, however I did manage to boot it with just the 256 meg stick
    in, that was a a very long drawn out affair as you can imagine!!!

    So both sticks seems to work but not together.

    This is my mobo

    Memeory is on page 18, however confusingly my slots
    go blue blue black black

    Howveer they show green purple green purple in the pic but refer to
    blue and black in the text (page 18).

    Now I am pretty sure initially I had 256meg in dimm 1 and 1 gig in dimm 3
    I seem to remember I had wanted them the other way around but that was the
    way I could get them to work. Worth remembering the system came with 256 meg
    in dimm 1 so it it used to living in that slow and probably makes better
    contact there.

    Two thinks seem to happen when I try and use both sticks together, one is
    that is gets to what I believe is called the POST screen, which is a blue
    with thinks like press F1 to enter set-up, and then just sits there doing
    normally it only waits there for a short while and then goes to a screen
    I can select either windows or windows recovery (or ubuntu).

    The second case is (IIRC) that it starts booting into windows but crashes at
    various stages
    (reboots) before booting up. I had put this down to windows trying to make
    of the dual channel memory at this stage and it not working because the
    memory is not matched.

    It has helped me a bit typing this in because it has forced me to think more
    clearly about things.
    I now think that the previous paragraph is wrong, I probably had them in
    single channel becuase
    it got further in that case. Seems more logical that I was trying to use
    dual channel when it stuck
    at the post screen, would that make sense?

    Currently I am runing with 1 gig in dimm 2 (slot 2), prior to that I was
    running with it in
    dimm 1 (and before that before the new problem with 1 gig in dimm 1 and 256
    in dimm 3.
    **Note according to the mobo link this config should not work (it's not
    shown anyway!!)
    A single moduel should only work in slot 1 or slot 3 not slot 2, *unless* my
    slot 2 is really slot 3?
    That would kind of make sense if you go by the clour of the slots (not the

    It seem to me I shoud be able to add the extra 256meg, I would have to put
    it in slot 4
    now I think, although according to "colour theory" I can't add another
    module with this config.

    I guess I will have to have another 'fiddle about' with the memory modules,
    I have cleaned the
    256 stick a bit which might help.

    I will give it a go later but I am wary about messing with it as I was
    unable to boot for several hours
    after I first got the problem and I only have one working computer, this

    I am going to get a new one though, this is 6years old, it's OK but I think
    an upgrade is due soon.
    R. Giggs., Aug 15, 2012
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  2. R. Giggs.

    R. Giggs. Guest

    I would add that cleaning the heat sink worked, it was well blokced and the
    as on most of the ime before even on very low CPU, it is much better now
    the fan only comes on after really heavy cpu usage and sometimes not even
    infact when I did get it booted up I had to check I had reconnected the CPU
    power becuase it was not coming on at all!!
    R. Giggs., Aug 15, 2012
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  3. R. Giggs.

    R. Giggs. Guest

    I just eneterd the set-up and it said I had 1 meg in 'module 2' IIRC
    so it seems that is dimm2 which is a setup not describe in the manual
    so I will have to put it in slot 1 or 3 if I want to add another module.

    It dirty inside the computer and it's east to knock black dirt all over the
    place including in the slots. I will try a bit of a hoover out but I know
    that is
    not recommended but I have done it before and it has not damaged it, but I
    be careful anyway.
    It's hard to get at the memory slots because of cables which are covered in
    I should be braver and disconect some of them, they are all tied together as
    I guess I shoudl break the ties and tie them myself afterwards.

    Next time I get stuck at the setup screen I shall enter it (if I can) I wish
    I had tried
    that before but I didn't!!
    R. Giggs., Aug 15, 2012
  4. R. Giggs.

    Paul Guest

    I think you sent three messages. You may have had a clock setting problem
    when sending the first message.

    In any case, your motherboard is S939 (AMD). Some of the processors used
    there, weren't true dual channel. They have a "bias" and that bias is
    reflected in the manual, in the memory population table.

    Don't worry about the colors. That's just the color of plastic
    and doesn't affect operation. Instead, pay attention to the position
    of the slots shown in the manual, versus the position of the slots
    on the actual motherboard. As long as the motherboard is oriented the
    same way as the manual, you should be able to make sense of it.

    The table has four columns, corresponding to the four DIMM slots.

    The first and third column, are for single channel mode. If you
    have only *one* stick of RAM to use, you start by filling the
    first and third column. If your DIMMs are mismatched in size
    (1GB module plus a 256MB module), then they go in the first and
    third slot. That's because, the older AMD processors, need "matched"
    size modules for dual channel operation. If you put 1GB in the
    first slot and 256MB in the second slot, it's an attempt to run
    dual channel, but the amount of RAM doesn't match.

    So what that says, is if you're going to use "any ole RAM in the drawer",
    you start by filling slot one and slot three. The other slots are useful,
    when using carefully matched stuff. So if you had two 1GB modules, each
    module having 16 chips on it, you could put those in slot one and slot two.
    Or slot three and slot four.

    The way the original S939 processors worked, is instead of being
    dual channel (independent), they operated like two train locomotives
    tied together. They operated in "128 bit mode", the exact same control
    bus information goes to both DIMMs. If the DIMMs were mismatched
    (two 1GB modules, but one module had 8 chips total, the other module
    had 16 chips total), then those modules could not operate in 128 bit
    mode, because each module would need different data bursts for RAS/CAS

    I think you're on the right track. Stick with the slots the modules
    have always been located in. If they were in slot one and slot three,
    then you can use any combo of the two DIMMs in those two slots.
    You could try...

    Slot one Slot three
    256MB ---
    256MB 1GB
    --- 1GB
    1GB ---
    1GB 256MB
    --- 256MB

    As far as I know, all of those should work.

    The other nice thing about the DIMMs being in the slots, is if
    you're working in a dirty environment, the DIMM in the slot helps
    keep the contacts clean. A little bit. It depends on how mobile
    the dirt is, how sticky the mess, as to how fouled the slots
    will become when cleaning or moving things around. I'm not a big
    fan of abrasive cleaning (pencil erasers, sandpaper, emery cloth),
    and instead, I try to use isopropyl alcohol and some kind of cloth
    that won't leave a residue later. You would also want to use
    ESD precautions while working on the PC, like your antistatic
    strap. You connect that to the chassis, and to your wrist, while
    working on the chassis.

    If I had to blow the dirt around (take PC out back, use the shop
    vac in reverse, and blow air into the case), I'd leave the
    DIMMs in the DIMM slots, to try to keep the slot clean. There
    are many kinds of dirt, and some will be more intrusive than
    others (like smoker's film). Static is generated, any time there
    is dust in an air stream, so whether you use a vacuum cleaner,
    or use a blower in reverse, or a can of Dust Off, there is always
    a danger of surface static buildup. And that danger, comes from
    the dust you're trying to remove. It moves the static charge.


    You should get yourself a memtest86+ floppy, and use that to
    test the memory configurations. The program is self-booting and
    no OS is required. You could, for example, disconnect all hard
    drives and optical drives, and still use memtest86+ via the floppy
    drive. Only one complete "pass" on the memtest86+ screen is
    required, for a quick check. If there are "stuck-at" faults
    on the DIMM, in other words failed memory locations at the
    same fixed addresses, they will likely show up in a single pass.
    If, on the other hand, the memory faults were transient and
    happened at different addresses on each pass, then other test
    tools would be needed. Since Windows is crashing at boot, I
    think you could have a bad memory location. Scroll down to the
    middle of this page, and get a copy of memtest86+ you can use.
    Use the best version, based on what devices you know you can
    boot from on your computer. If you have a floppy, you can use that.

    Later AMD processors (Rev.E or later?), have perfectly
    flexible memory support, and you can use any combination
    of DIMMs in any slots you want with those. But I'm going to
    assume you have C0/CG/D0 kinda revision, and so on those,
    slot one and slot three "are your friends". Use the nominated
    single channel slots, when in doubts about your processor

    Paul, Aug 16, 2012
  5. R. Giggs.

    R. Giggs. Guest

    OK thanks a bunch, just a quick reply to say it is according to cpu-z
    I will reply agian later when I have read it properly
    R. Giggs., Aug 16, 2012
  6. R. Giggs.

    R. Giggs. Guest

    Well it looks like I have revision R perhaps

    it says Familly F ; Model B; stepping 1;
    Ext. Familly F ; Ext Model 2B; Revision BH-4E

    But the revision number is confusing, might be B.
    However as it is running in an invalid mode (apparently)
    that suggests it may be Revision E.
    R. Giggs., Aug 16, 2012
  7. R. Giggs.

    Paul Guest

    There is a decoder here.

    Third table down, shows some possibilities.

    I'm guessing BH-E4 is Rev.E and that has the flexible
    memory controller that accepts anything. You should be
    able to stick your DIMMs in any slot, and get them to work.

    Revision E includes "virtual single channel mode", and with your
    unmatched DIMMs, that's the most likely operating mode.

    My guess is then, that all your DIMM slots should work.

    Now, on with the memtest86+ testing...

    Paul, Aug 16, 2012
  8. R. Giggs.

    R. Giggs. Guest

    Yes i have read some other post which suggest it it revision E4 ie

    The normal A64 Venice has two revisions

    Venice E3 = DH-E3
    Venice E6 = DH-E6

    The A64 San Diego is SH-E4

    The E4 we're speaking of in this thread is a Manchester.

    Manchester = BH-E4
    Toledo = JH-E6

    So it seems to be a manchester E4.
    So given that I shoudl be able to stick the 256meg in any slot and it should
    although I have previously tried that, it might be the connection of the
    module are a bit
    I have cleaned the contacts a bit with some tissue paper now, which may
    I don't have isopropyl alcohol , so if that does not work I might try some
    kitchen cleaner - lol..

    It has isopropanol gylgol ether in it amongst other things lol. I am not
    worried about doing damage
    as it dies not work anyway and I don't really think it will do any harm.

    My main concern is I do not like fiddling about with it incase I can't
    reboot, although I was
    messing with it last night and I could always boot with one stick in it, so
    I am not overly worrried.
    R. Giggs., Aug 16, 2012
  9. R. Giggs.

    R. Giggs. Guest

    I woudl add it runns fairly well on 1 gig, can't tell the difference much
    of the time, it is just that is slows more often when it is low on memory
    and has to swap.
    R. Giggs., Aug 16, 2012
  10. R. Giggs.

    R. Giggs. Guest

    Thanks I will give it a go later, I think I have memtest on disk
    from when I had earlier problems.

    I remember now, I bought a 1 gig stsick, I had to send it back
    as memtest showed some problems, or maybe it just showd problems
    when I had both sticks in, It was a while back so I can't remember
    clearly. I thnk I may have posted about it on here so I will see if I can
    find the thread somehow

    Here is is, I am Colin Trunt :)!topic/[1-25]
    R. Giggs., Aug 16, 2012
  11. R. Giggs.

    Paul Guest

    There shouldn't be that much difference between 1GB and 1.25GB (i.e. adding
    the second DIMM). Note that the memory speed supported by default, can
    change between the two configurations. If two DIMMs are on the same
    channel, some motherboards drop the speed to DDR333, when the sticks
    are DDR400 capable. With the one stick, it should run at DDR400.

    When you run dual channel, like put a single 1GB on each channel for a
    total of 2GB, it will also run DDR400 speed. It's when two DIMMs show
    up on the same channel, it slows down a bit.

    In addition to that, there can also be a Command Rate setting
    in the BIOS memory adjustment screen. The options are Command Rate 1T
    and Command Rate 2T. In the 2T case, commands are placed on the bus
    for two cycles, and the strobe catches them on the second cycle. This
    adds extra setup time to rising clock edge, and may help with a
    heavily loaded bus (2 DIMMs, double sided, on a channel). In
    terms of the level of stress, the settings would go like this.

    Command Rate 1T, DDR400 <--- highest performance
    Command Rate 2T, DDR400 <--- may work, must "user test" before using Windows
    Command Rate 1T, DDR333 <--- probably good enough for 2 DIMMs in a channel.
    Command Rate 2T, DDR333 <--- very conservative - helps with bad processor
    or out of spec RAM perhaps.

    Enthusiasts would work their way through the chart, testing how much
    their system could take. Tools like Prime95, and test times of 4 hours
    error free or more, might be used as a final acceptance test.

    You can use CPUZ program from, to display some info about
    memory settings. And perhaps you can figure out from that, what
    your BIOS has decided to do.

    Personally, in any case, if I had to choose between 1GB DIMM or
    using 1GB + 256MB DIMM, I would use the former configuration. It's
    the best for your S939. If I wanted to improve things a bit,
    I'd buy an additional 1GB DIMM, and run 2x1GB (one DIMM on each
    channel, like slot 1 and slot 2). The BIOS will likely use the
    more aggressive memory setting that way.

    I haven't gone into a discussion of CAS timing. CAS3 is industry standard
    (boring). CAS2.5 or CAS2 is tighter CAS, less latency. And used to cost
    more. At retail, you'll probably only find CAS3 now. As DDR memory is
    approaching obsolescence. I think Kingston may have stopped selling it,
    both SDRAM and DDR. Crucial may still have it, not sure. Newegg still
    sells some of it, even with name brand, but it's CAS3. If you must stick
    with the six year old machine (and I have lots of old gear here),
    look at getting one or two. It may help a bit, if you want to
    continue using the machine. One of my DDR400 machines here, has
    2x1GB CAS2, and the other has 2x512MB CAS2 (cheaped out... :) )

    G.SKILL 2GB (2 x 1GB) 184-Pin DDR400 (PC3200) F1-3200PHU2-2GBNS $56

    You could run a pair of those, and store your existing RAM in
    a desk drawer for emergencies (like, the need to test).

    One other thing I've noticed, as a random comment, is the
    error rate on DDR seems to be worse than DDR2. I was surprised,
    that with all of my tuning and so on, my favorite game used to
    mis-behave a couple times a month. I dismissed this as "software bugs"
    at first. When I got two DDR2 machines to play with, I noticed that
    using the same test conditions, I saw fewer of those kind of events.
    Which suggests to me, that the error rate due to things like
    bus noise, is getting better on the newer machines. Small sample
    size etc etc...

    Paul, Aug 16, 2012
  12. R. Giggs.

    R. Giggs. Guest

    Right I will read that in a minute but firstly I must report success!!

    I tried putting the 256meg in slot one but it rebooted during startup.
    Then I tried something I had a bit of a 'hunch' about, I took the stick out
    and then
    put it back in again, but this time I changed the method of insertion. I had
    pressed the right side of the module in first, or both together, this time I
    pressed the left
    side in, which is slightly unnatural for be being right handed. I noticed
    it seemed to go
    in further than normal perhaps and I could almost feel it making contact.

    Anyway it booted up fine!!!
    R. Giggs., Aug 16, 2012
  13. R. Giggs.

    R. Giggs. Guest

    You are probbaly right about the speed thing ( I hate to use the word
    probably as you
    most certainly know what you are talking about, that's why I came here in
    the first place,
    I though about going to some of the web computer forums, but I have been to
    them before
    and lot of people have little idea what they are talking about or will make
    an obviously wrong
    instant diagnosis, or something which makes litte sense, so I came here
    because I have the upmost
    respect for you and your knowledge!!).
    I'd say most of the time I will notice little difference, but I have that
    extra bit of ram to reduce paging
    or whatever.

    Anyway here is the cpuz full report

    Number of CPUs 2
    CPU#1 APIC ID = 0
    Name AMD Athlon 64 X2 3800+
    Code Name Manchester
    Specification AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
    Family / Model / Stepping F B 1
    Extended Family / Model F 2B
    Brand ID 5
    Package Socket 939
    Core Stepping BH-E4
    Technology 90 nm
    Supported Instructions Sets MMX, Extended MMX, 3DNow!, Extended
    3DNow!, SSE, SSE2, SSE3, x86-64
    CPU Clock Speed 1989.6 MHz
    Clock multiplier x 10.0
    HTT Bus Frequency 199.0 MHz
    L1 Data Cache 64 KBytes, 2-way set associative, 64 Bytes line size
    L1 Instruction Cache 64 KBytes, 2-way set associative, 64 Bytes line
    L2 Cache 512 KBytes, 16-way set associative, 64 Bytes line size
    L2 Speed 1989.6 MHz (Full)
    L2 Location On Chip
    L2 Data Prefetch Logic yes
    L2 Bus Width 128 bits
    CPU#2 APIC ID = 1
    Name AMD Athlon 64 X2 3800+
    Code Name Manchester
    Specification AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
    Family / Model / Stepping F B 1
    Extended Family / Model F 2B
    Brand ID 5
    Package Socket 939
    Core Stepping BH-E4
    Technology 90 nm
    Supported Instructions Sets MMX, Extended MMX, 3DNow!, Extended
    3DNow!, SSE, SSE2, SSE3, x86-64
    CPU Clock Speed 1989.6 MHz
    Clock multiplier x 10.0
    HTT Bus Frequency 199.0 MHz
    L1 Data Cache 64 KBytes, 2-way set associative, 64 Bytes line size
    L1 Instruction Cache 64 KBytes, 2-way set associative, 64 Bytes line
    L2 Cache 512 KBytes, 16-way set associative, 64 Bytes line size
    L2 Speed 1989.6 MHz (Full)
    L2 Location On Chip
    L2 Data Prefetch Logic yes
    L2 Bus Width 128 bits

    Mainboard and chipset
    Motherboard manufacturer MSI
    Motherboard model AMETHYST-M, 1.0
    BIOS vendor Phoenix Technologies, LTD
    BIOS revision 3.41
    BIOS release date 12/26/2005
    Chipset ATI RS480 rev. 10
    Southbridge ATI SB400 rev. 00
    Sensor chip SMSC 6001
    Graphic Interface PCI-Express
    PCI-E Link Width x16
    PCI-E Max Link Width x16

    DRAM Size 1280 MBytes
    DRAM Frequency 199.0 MHz
    CAS# Latency 3.0 clocks
    RAS# to CAS# 3 clocks
    RAS# Precharge 3 clocks
    Cycle Time (TRAS) 8 clocks
    Bank Cycle Time (TRC) 11 clocks
    DRAM Idle Timer 16 clocks
    Command Rate 2T
    # of memory modules 2
    Module 0 Infineon DDR PC3200 - 256 MBytes
    Module 1 DDR PC3200 - 1024 MBytes

    Windows version Microsoft Windows XP Home Edition Service Pack 3
    (Build 2600)
    DirectX version 9.0c

    Hope that displays correctly!!
    I will post text if it does not.

    It says T2 and withthe clock at 199Mhz I think that is DDR400 mode?

    I do not know if I wil be able to get T1, not sure if it is something I can
    change in the BIOS but
    I have never looked for it before. I did notice I could boot into a
    diagnostic mode in the BIOS
    but I chickend out of doing so!!

    Anyhow now I canuse two modules I plan on getting an extra gig but it needs
    to be matched memory.
    I just noticed that there is no brand (above) given for the 1 gig stick, the
    256meg says Infineon.

    I note mine are what would be a dual channel configuration at the moment not
    sure if that would
    work with different sized sticks.

    I think it does run a little smoother some things, 256meg is not a lot but,
    the operating system needs
    a fair bit for itself so it should feel like more than a 25% increase in
    memory, but I am a bit out of
    my depth there lol. A lot of it might be pyschological, you just think it is
    faster because you added memory.

    I am planningon getting a ne machine soon though but I would like to add an
    extra gig to this and try
    and get it running matched memory. I would feel more comfortable tinkering
    around with a second
    machine as backup because then I can get on the net if I have a problem, and
    it's handy having internet access
    anyway, I don't think I coud survive a day without it!!
    My old machine is a cryic 300, it has packed up totally no, but I could use
    it as (a extremely slow)
    back up untill about 4 years ago. I could use my mobile phone as leat
    resort, but that would be painful!!

    Anyway thanks for your help, I look further into the stuff I do not
    understand so well later
    4 years ago. I also need to check which memeory I should get. Plus I might
    need advice on
    a new machine, probaly an i3 or i5 but I am not well up on the new hardware,
    I just look for the one
    with the highest PassMark, this one is rated at 1.043.

    But thanks once again I really appreciate the help!!!
    R. Giggs., Aug 16, 2012
  14. R. Giggs.

    Paul Guest

    That's pretty good. It's using "DRAM Frequency 199.0 MHz" = DDR400
    and "Command Rate 2T". You have two modules in the same channel, so
    I might be happy with it that way.

    If you dropped down to just the one stick, you'd hope to see
    a tighter setting, but if it didn't change, it wouldn't be the end
    of the world. My Intel chipset DDR system, is fixed at Command Rate 2T
    and you can't change it. And I have another system here, where
    the command rate was fixed as well. These are just controls
    to fiddle with, when you're bored.

    Some posters using those S939 systems, used to get pretty ticked
    about the memory settings (didn't like to see it running DDR333),
    so they'd spend hours playing with that stuff :)

    Paul, Aug 16, 2012
  15. R. Giggs.

    R. Giggs. Guest

    Well I woudl not be dropping down to 1 gig as I had previously been running
    on 1 gig
    and it didn't appear to be any faster although it might have been faster in
    situations, but not that I noticed.
    The extra memory allows my browser to keep more 'tabs' cached in memory for
    there is a significant delay when they are not cached and it is very
    noticible and massive compared
    to any gain I would gain from getting T1. For example I clicked one tab and
    it too 10 seconds to load!!
    (I have seen longer than that) normally it is a fraction of a second. If I
    could half that to 1/2 a fraction of
    a second ti woudl make little difference.
    It might make a diffference to something like game play when you are running
    from memeory, but I
    don't tend to play those sort of games, so no gain for me there.

    I have been running pretty OK on this set-up but I shall try to get a 1 gig
    stick, slight problem
    in that I am unsure what brand my current 1 gig stick is, cpuz gives no

    Another problem is it needs to be non-ECC supposedly.

    I know I bought the one current one gig stick from here.

    I have a feeling I bought the Integral brand before, I don't think I was
    of matched memory at the time.

    It makes no mention of ECC or non ECC. unfortunately.
    I also notice there are two there same for diffferent prices, or so I
    thought!! It seems
    one is 2.5v and the other 2.6v. Fortunately mine is 2.5v which is cheaper.

    Then there is ebay
    That says it is non-ecc
    but it data sheet here says otherewise, ie ECC

    However an ECC one might work anyway


    DRAM - Can I install an ECC DIMM on a Non-ECC motherboard?
    Most motherboards that do not have an ECC function within the BIOS are still
    able to use a module with ECC, but the ECC functionality will not work.

    Keep in mind, there are some cases where the motherboard will not accept an
    ECC module, depending on the BIOS version.


    Looks like my best option might be to buy a 1 gig stick from PC-World, there
    is one local to me,

    more convienient than ebay,

    Anyway I think I will reboot and take a look at what is says on the 1 gig
    stick, I will also

    look at the BIOS settings.
    R. Giggs., Aug 16, 2012
  16. R. Giggs.

    Paul Guest

    You want to match the chip configuration of the existing 1GB DIMM.

    I assume your existing 1GB DIMM has sixteen chips.

    There are two ways to make the modules. (16) 64Mx8 chips is one way.
    That's low density. My 1GB modules are made that way.

    (16) 128Mx4 chips is a second way. That's called "high density".
    It wouldn't match your existing module. The x4 format doesn't work
    with all chipsets (like, Intel hates that, while AMD probably
    tolerates it, but with the potential for a drop to DDR333 rate).

    I don't think (8) 128Mx8 are available for DDR. That would be a
    third way to do it. Whether stuff like that exists, depends on
    the price of the chips. If the chips cost a penny more, then
    they wouldn't use them :)

    So if you can look up the chips themselves, and verify the chip interface
    is x8 (8 bits wide), then that goes a ways to proving it's going to match.

    Some early BIOS for S939 motherboards, did a little too much "matching"
    and compared too many fields in the SPD data coming from the DIMM. But once
    the BIOS got updated, they stuck with rows,columns,banks,ranks as the
    matching criterion.

    At one time, Ebay was quite a source of "high density" modules. I suspect
    there were a fair number of returns, when the buyers found out what they
    had got. The adverts then started to become a little more honest about
    what you were getting. You don't want high density, because your existing
    module (bought at the store), is going to be a low density one. And
    your mission here, is to "match" the existing one. High density modules
    are available almost exclusively, on Ebay ("the curse of Ebay"). Since
    you have a store bought module, you'll want another low density one
    with the 64Mx8 chips.

    The voltage issue is bogus. DDR up to DDR333 speed, JEDEC set the voltage
    to 2.5V. When the topic of DDR400 came up in the JEDEC committee, the
    participants said "we won't agree to this, unless the voltage is set
    to 2.6V in the spec". So the new speed standard, passed in JEDEC, and
    became official. The 2.6V was used, as a means to improve yield. And
    that turned out to be unnecessary, as it turned out to be easy to make
    DDR400 after all. So strictly speaking, the DDR400 product you see
    advertised as "2.5V", that's just a dumb mistake. No extra points are
    awarded for accidental "undervolting". JEDEC allows all those DDR400 chips
    to run at 2.6V.

    As for your motherboard, the VDimm regulator is likely applying
    2.65V to your existing DIMMs right now. The only boards that
    do something like deliver exactly 2.5V, are some server boards.
    But anything in the desktop market, the designers winked at one
    another, and had no problems giving it a little more. Just to
    cover all possibilities. It really doesn't hurt anything. As
    far as I know, any DDR can take 2.7V long term, so being a little
    off doesn't hurt. (The latest generation, the processors can have
    a tighter spec on voltage. For example, DDR3 is 1.5V and an Intel
    processor may have a stated spec of 1.65V max. So there isn't as much
    room for fun there.)

    If you go ECC, then *all* the modules plugged in should be ECC.
    The BIOS will not like it, if some modules are ECC and some not.
    AMD processors have a history of supporting ECC, as far as
    architecture goes. And AMD processors, when the BIOS detects
    all ECC modules, can use functions such as "scrub", to review
    the contents of memory, and correct the contents, on the fly.

    An ECC module is x72 wide, and has 9 chips per side on the higher
    capacity modules. (That't the unbuffered or "UDIMM" type.)
    If the "ECC lane", the one with the extra 8 bits
    is not wired up, the chip just floats on the DIMM. So if your
    motherboard was not designed for ECC, then I don't think that
    hurts anything. But it's not generally a good idea to mix the
    two types, and if you were to use some of each type, you'd
    hear a "now cut that out!" style beep coming from the BIOS
    at POST :)

    Paul, Aug 17, 2012
  17. R. Giggs.

    R. Giggs. Guest

    Well from what you have told me the one at the store near me must
    be non-ecc as itonly has 8 chips on it. MInd you I have seen some
    on amazon with 8 chips described as ECC

    Mine has 16 chips on it as I recall 8 on each side, same as the one above

    I need to try and figure out what brand mine is, I had a look with it in the
    but it had no lable on it, so I will have to take it out and look at the
    chips to
    see if I can get a clue from there. As I said I got it locally so best to
    try their first if
    I can't find the brand.

    One thing which concerns me is it says on the motherboard spec

    This mainboard DO NOT support the memory module installed

    with more than 18 pieces of IC (integrated circuit).


    Back to me, I can't change the font back!!!

    I am unsure what that means as I am pretty sure I have 24 IC's installed
    already ie 1, 2x8 and one 1x8 = 24 in total!!!
    R. Giggs., Aug 17, 2012
  18. R. Giggs.

    R. Giggs. Guest

    Right it also says for matched they should be the same type and density, so
    not necessarilly the
    same brand?

    I guess they just want the same chips layout, which shoud ensure they work
    on the same clock cycles?
    Which would be all that RAS and CAS stuff?
    R. Giggs., Aug 17, 2012
  19. R. Giggs.

    Paul Guest

    16 chips, is enough for non-ECC UDIMM (unbuffered, x64 wide)
    18 chips, is enough for ECC UDIMM (unbuffered, x72 wide)
    21 chips, is enough for ECC RDIMM (registered, x72 wide, server memory)

    You don't want server memory.

    You also want to match what you've got, 16 chips.

    The match is on rows,columns,banks,ranks.
    The row address is delivered on RAS (row address strobe)
    The column address is delivered on CAS (column address strobe)
    Rows times columns, is a block of memory bits, inside a memory chip.
    The blocks form four banks. So the third logical dimension inside
    the memory chip, is a bank. There are four blocks, arranged above
    one another, and bank is along the Z-axis.

    The number of banks changes, as the technology advances. Banks
    are used to drop the clock rate inside the chip. So when the new memories
    go faster and faster, the clock inside stays relatively the same, and
    it's done by using more banks.

    Now, all of that, was inside a memory chip. You want the logical
    dimensions of the memory chips on both modules to be the same.
    For AMD, that's so the same address during RAS, CAS, and BA (bank address)
    can be used. It's so the control information is the same in both channels.
    Not all hardware works that way though, and there are more flexible arrangements
    than the old AMD one, which allow each DIMM to have its own flavor of control.

    The ranks, are groups of chips on the DIMM. A rank is enough chips to make
    a 64 bit wide array (for your kind of DIMM). Say we're using chips which are
    x8 wide. It takes eight of those chips to make a rank. There is a rank
    on each side of the module. So, a total of two ranks.

    If you had high density DDR, it takes (16) of the x4 chips to make a rank.
    The entire DIMM, then ends up being a single rank. So mixing a high and
    a low density DIMM, is a non-starter, and causes reversion to single
    channel mode on the Rev.E or later processor.

    Server memory, can have as many as four ranks on the same DIMM. That is,
    a total of 36 memory chips, plus the register and PLL located in the
    center of the DIMM. Such memories work on Opteron servers for example.

    Fully buffered memory (Intel server thing) or FBDIMM, uses a larger
    chip in the center of the DIMM, which buffers *everything*. Whereas,
    on an RDIMM, only the address/control bus is buffered, and the data is
    unbuffered. On an FBDIMM, an entirely different interconnect standard
    is used, to connect DIMMs together. In terms of allowing all sorts of
    wacky things to happen, an FBDIMM has the most latitude to be
    creative when building flavors of DIMMs.

    But your world right now, is rather simple. Look for the 16 chips,
    try to buy a branded RAM (not "high density" off Ebay), and you
    should be fine with your DDR400 purchase.

    Paul, Aug 17, 2012
  20. R. Giggs.

    R. Giggs. Guest

    Right, thanks a lot for that.

    I have had a look at the BIOS and there is no option to change to T1 from T2
    That is not a surprise really, these machine are targeted at the mass
    market, not those who tinker
    and modify.
    I also looked at the 1 gig module and it is a Hynix 611AA A
    HY50U12822CPT-043, that 5 might be an S
    So seems sensible to get another similar.
    I also move the 1 gig to slot 3 single channel setup.
    CUPZ still the same, ie T2

    It has 8 chips on each side, so that woud be low density, I seem to remember
    from before
    not to get high density.

    This would seem to be suitable

    Cheap at £10.99 but that might suggest it is faulty (lol). Also the brand is
    unclear as several are listed.

    Another I could bit one but ECC not mentioned, is that a chip in the middle?

    Another here.

    And another here.

    So I will have to plump for one of those. The last one seems fine, 100%
    feedback and ticks all the boxes
    I think, it say low density when I google it else where, so I may as well
    get that one.
    R. Giggs., Aug 17, 2012
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