VA503+: maximum installable memory? DIMM size limitation?

Discussion in 'FIC' started by Doug, Nov 15, 2005.

  1. Doug

    Doug Guest

    I'm just wondering, can the 504+ handle more than 256MB of memory? Every
    time I've tried (with one 256MB stick and assorted other sticks of PC100 and
    PC133 flavors and sizes), the system boots but will not run through memtest
    without erroring out. If I run the sticks by themselves memtest runs fine.
    Will the 503+ work w/256MB PC100 DIMMs? I've noticed the Tyan s1590 (also
    based on the VIA MVp3 chipset) doesn't recommend any DIMMs over 128MB in
    size. Is this also true of the 503+? All my 503+ manual states about 256MB
    DIMMs is that none were available for testing.
    Doug, Nov 15, 2005
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  2. The VA-503+ can handle up to 768 MB RAM, consisting of 3 256 MB DIMMs.
    The MVP3 chipset can handle a memory density of up to 16 MB per memory
    chip. That would mean a 256 MB DIMM must consist of 16 memory chips,
    each one containing 16 MB. The 256 MB DIMMs that are more common these
    days usually consist of only 8 chips, which will not work because they
    consist of 32 MB chips. (In the case of ECC RAM, one extra chip per
    side is allowed for the ECC function, so a 256 MB ECC DIMM would have a
    total of 18 chips).

    Other chipsets from this time period also have the same size
    limitations. For example, the Intel 440BX. When these chipsets first
    came out, they were designed to handle up to 16 MB/chip, but only 8 MB
    chips were available at the time. When the 16 MB chips started coming
    out, they worked fine in most of these boards, but some required BIOS
    updates to sort out compatability problems.

    As for your problems getting the DIMMs to run together, this is often a
    result of more memory modules placing more burden on the memory
    controller. I do not recall the particulars of the VA-503+ off the top
    of my head, but here are some general tips:

    Loosen memory timings in BIOS. Set CAS Latency to the highest number,
    which would be 3. Also, set the Memory Timings (I forgot the exact
    name) more towards "Slow" and away from "Turbo".

    If the VA-503+ gives you a way to adjust the memory voltage or I/O
    voltage, try bumping it up a notch. The normal DIMM voltage for regular
    SDRAM is 3.3 V. Try bumping it up to 3.4 V.

    While you are at it, you may check for any BIOS updates in case any
    memory issues have been addressed.

    By the way, you may hear that the MVP chipset has a maximum *cacheable*
    memory size of 255 or 256 MB. Basically, what this means is that if you
    put more memory than this in your computer, the overall performance will
    actually go down. In practical terms, this means that unless you
    actually need more physical RAM than 256 MB, you are better off staying
    with 256 MB. On the other hand, if you regular need more than 256 MB,
    then you will still benefit from the added RAM, because the it is still
    way faster than having your computer access the swapfile on your hard drive.

    I hope this helps.

    Alex Zorrilla, Nov 15, 2005
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  3. Doug

    Doug Guest

    Well, that cuts it. I guess I'll just stick with 256MB then. It's
    interesting that the manual for the Tyan s1590 (also
    based on the VIA MVp3 chipset) didn't mention the 256MB limit for cacheable
    memory. I never knew about the 16MB per memory chip limitation. Thanks.
    Doug, Nov 16, 2005
  4. Doug

    Roger Hunt Guest


    Does this apply to the PA-2013 as well?
    I suspect it does, as I always regarded the 2013 as the ATX version of
    the 503+, but it would be handy to know for sure before I get hold of
    one (to replace my much loved and melted 503+).
    Roger Hunt, Nov 17, 2005
  5. Yup, sure does. Same thing goes for the VA-503A, and just about any
    other MVP3 chipset motherboard.
    Alex Zorrilla, Nov 17, 2005
  6. Doug

    Roger Hunt Guest

    Thanks. I'm looking forward to firing up this here K6-2+/500 - should be
    good for 10-15% overclock. And I'm also going to play with an ancient
    (ISA card) Trojan Light Pen, and Win3.1.
    Roger Hunt, Nov 17, 2005
  7. My 503+ only has 2 DIMM slots, so the max memory would be 512M. I can
    confirm from recent experience that a 256M stick with 8 chips doesn't work
    (actually it does, as a 128M stick). To achieve long term (error-free 24
    hour memtest) I set DRAM timing to "Normal" and CAS to "3". Trying to run
    with faster settings usually failed with single bit errors on test #6 with a
    ones-heavy test pattern. My 503+ is offline at present as I'm using the KVM
    with a neighbor's sick IBM Netvista. I'll verify my exact settings over the
    weekend and report back.
    J. Michael Milner, Nov 18, 2005
  8. I double-checked my chipset settings and it appears that the only thing my
    system is sensitive to is the CAS value - I need it to be 3. I've used both
    "turbo" and "Fast" DRAM timing without problems as long as CAS is 3.
    Setting DRAM timing to "Normal" and CAS to 2 causes random single-bit errors
    in a 24 hour memtest run.
    J. Michael Milner, Nov 23, 2005
  9. Doug

    farmuse Guest

    sure the 503A isn't the MVP4 ? ata66 etc
    farmuse, Nov 26, 2005
  10. MVP4 is MVP3 with integrated Trident graphics thrown in. Otherwise,
    they are basically the same chipset.

    You are right about the 503A supporting ATA66 and integrated sound. It
    uses the VIA 686A southbridge chip instead of the VIA 596B that is found
    in the 503+. They do use the same northbridge, though, which is what is
    most often used in naming the chipset.

    Maybe they should call it MVP3-1/2. :p
    Alex Zorrilla, Nov 28, 2005
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