N6800 vid not able to use full 3 GB MEM on A7V333 but works for 2.5GB or lower

Discussion in 'Asus' started by Liquid, Jul 4, 2006.

  1. Liquid

    Liquid Guest

    Hi all,

    I having a frustrating problem with upgrading my video card to an ASUS
    N6800 (Geforce 6800 512MB of ram) on an ASUS A7V333 motherboard. At
    first I couldn't get it to post ASUS tier 3 tech support said to RMA or
    exchange it.

    I finally got it to work after giving up on bios changes. I tried just
    1GB DIMM and it worked! Problem is I can only get 2 1GB DIMM's to
    work. Or 2 1GB DIMM's and one old 512MB DIMM. The new memory is 3GB of
    Corsair XMS PC3200 part number CMX1024-3200C2PT for the 1GB sticks.
    The old memory is 512MB Corsair XMS part number CMX512-3000C2.

    I can get all 3GB of memory to work with my old video card ASUS V8440
    (Geforce 4 4400 ultra) no errors with memtest86. I'm unsure as what is
    the culprit. I'm thinking the vid card, motherboard or power supply
    (which I have a gut feeling for). The power supply is an Antec 430
    true power came with case wanted to get better one but was free. Am I
    correct that my board uses a 20 pin power cable for the board?

    My 3.3 voltage goes from 3.24-3.26 is this the voltage the RAM runs
    under? Is this the problem? Do I maybe need a bigger/better power
    supply? I'm gonna run memtest86 tonight to see if it is stable with
    2.5GB. Will post any news. I would really like to max my board (3
    slots) to 3GB. Voltage for everything is stable line in ASUS PC Probe
    but 12v and 3.3v go up and down slightly. I just bought an APC smart
    ups 500 watt so I'll try connecting that too but I don't think I have
    "dirty" power.

    Also, when I called back tier 3 tech support with my finding they
    advised to run all memory of same size and manufacturer and part
    number. If memtest86 checks out will it be rock solid if I have to run
    a 512MB in the mix (getting same Corsair XMS series with free
    restocking if not needed). The 1GB sticks are same part number but 1
    is a different version only bought less then one week apart from
    newegg. On original vid card I had to put two of the same version in
    slots 1 and 3 instead of 1 and 2 to get no errors in memtest86 did get
    errors in test 5 on memtest86 moving blocks where the 2 goes to 3 slot
    I think. But OS didn't lockup was just checking memory didn't run OS
    that much before testing or stress it...

    Well, any help or insight to diagnosing this or advice would be GREATLY
    appreciated. This is buggin me I want to use my full 3GB and don't
    want to use my old vid card.

    Thanks in advance for any help,
    Liquid, Jul 4, 2006
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  2. Liquid

    Liquid Guest

    Memtest86 ran with 2.5 gigs without errors gonna try and clock down FSB
    for 3 gigs. Look forward to responses.

    Best Regards,
    Liquid, Jul 4, 2006
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  3. Liquid

    Paul Guest

    Three sticks of CAS2 memory should work as well as could be expected.
    With that loading, of three double sided sticks, downclocking the
    memory is a likely solution to whatever stability or memory errors
    you are getting.

    Motherboards tend to re-regulate the voltages coming from the
    power supply. DIMMs tend to have a small linear or switching
    regulator, for the memory voltage and for the termination
    voltage. Internally regulated motherboard voltages are not
    monitored on the hardware monitor chip, so the only way to
    verify what is actually being used, is with a voltmeter.
    In this case, the supply voltage is intended to be in the
    2.5-2.6V range, and does not come directly from 3.3V.

    In the fifth post down, there is a table of JP1/JP2 jumper
    position, versus DIMM supply voltage.


    According to this article, the default setting is already
    providing 2.78 - 2.85V, which is as far as I would go with
    memory that is not known to overvolt well. If you had some
    old BH5 based memory, then virtually any jumper setting
    would be valid. I certainly wouldn't run my Ballistix
    memory in a board like that, and use all possible jumper
    settings, because the high setting would fry my RAM.
    So stick with the default.


    Paul, Jul 4, 2006
  4. Liquid

    Liquid Guest

    Thanks Paul :)

    Unfortunately, that didn't get the 3 gigs to work I tried every
    arrangement of pins. On JP1 and JP2 I thought that would fix it. But
    it didn't thanks. That first part of the first link was very
    informative thanks.

    Good news is I figured out with just the 2 in slots 1 and 3 I can get
    150+ more megabytes per second in memtest86. It doesn't work with my
    old 512 pc3200 stick. But the 512 stick does by it self. I ordered
    another new 512mb stick of same series to go in middle and hopefully
    get 2.5gigs turbo instead of optimal (default slower). I convinced
    newegg to give me no restocking fee before I bought if it doesn't work.
    Hoping it does 2.5 gigs isn't bad I'm thinking of vista and games.

    I'm also bought an AMD 2600+ (highest supported) and was able to
    overclock the multiplier by 1 but got an error in prime95. So I
    clocked it down to only .5 over and about +3 the front side bus. Seems
    to be stable. The memory really seems to have speeded things up on
    turbo. Is it normal for an AMD chip to be able to be overclocked
    without modification? I bought a kit to connect the bridges to
    overclock think I would get better performance with that? Or if I'm
    able to move multiplier up am I already unlocked? Should I try a XP
    AMD 3000+ FSB 333 and clock down the FSB for more performance? It's
    only I think a 1.01 board but heard on ASUS discussions that it works
    to about 150 FSB.

    I'm going to try putting my old computer with pc power and cooling
    power supply and hook it up to main board without taking out of case
    but is only 275 watt. Hopefully that makes it work. I read on their
    website a new manual insert that pc2100 and pc2400 or 2500 can't
    remember which it is at moment work up to 3 gigs. But pc2700 only
    works with 2 gigs BUT, I did get the 3 gigs pc3200 to work with old
    video card :-/. I also tried turning down the FSB and latency all the
    way down wouldn't post with all 3 1GB sticks and changing voltage. I
    might try removing all jumpers on JP1+2 and see if that works or is the
    default jumpers same as no jumpers? I'm running out of ideas.

    Got anymore ideas Paul or anyone else? Thanks again for the help Paul.

    Best Regards,
    Liquid, Jul 5, 2006
  5. Liquid

    Paul Guest

    Well, here is a funny one for you:


    They suggest reducing the RAM voltage below the default setting.
    (That might reduce electrical switching noise a tiny bit, and
    since the RAM is not running at DDR400, it doesn't need a lot
    of voltage to meet timing. Reducing voltage is not a trick that
    gets used too often :) )

    You could also try not using Turbo, and setting CAS to 2.5 .

    I see a setting "SDRAM 1T Command Control" [Disabled] and in
    the Disabled state, that is supposed to use Command Rate 2T.
    The 2T option is a way to relax the timing on the address
    bus, when driving a heavy load. But the board is probably
    already using the Disabled value (unless maybe Turbo sets
    it back to the more aggressive 1T setting).

    As for the AGP slot itself, I'm not sure I see much in the way
    of viable options for tuning it. The manual mentions AGP 1x and
    4x as options, and there is no 2x option. I mean, if the video
    card makes a difference, then tuning the AGP slot might compensate
    for the problem a bit, but 1x is not really good enough for

    Paul, Jul 5, 2006
  6. Liquid

    Liquid Guest

    Yeah I already tried all that but thanks for the help and knowledge and
    links. I also just tried hooking up a different power supply to just
    the board and no difference. I think I'm stuck with 2 or I'll try the
    2.5 gigs when my 512mb module arrives.

    Do you have any idea what would the best chip to get the most
    performance out of this board? The manufacture says it can handle up
    to a 266FSB actual 133 double rate Athlon XP 2600+ which I just
    recently bought but, wondering if I could get more speed out of an
    Athlon 333FSB 3000+. The multiplier would prolly would be lower I
    think but, lowering the FSB to what I heard from somebody from ASUS's
    web boards that someone got running at 150 FSB actual double rate 300
    and then doing that you I would think you could increase the
    multiplier. I have revision 1.xx board I think it is 1.01.

    I know the revision 2 boards can handle an Athlon XP 3000+ FSB 333
    stock full speed and maybe all the 3gigs ram turbo. I might try RMAing
    the board if I can get a revision 2.0 and it has RAID included on board
    but, major pain swapping out a motherboard.

    How do you think an Athlon XP M (mobile) 2600+ or maybe higher would
    work? I've seen in auctions people saying they work in desktops and
    they overclock big time since they are made for laptops. Any ideas
    here, I want to squeeze as much power out of this system tell I build
    my next one some time after vista has come out and drivers are good for
    vista and prices come down from the influx in demand.

    I think I should have used my ISP to post and changed my email pisses
    me off Google doesn't let you do that damn them. Didn't know on other
    servers you can get thought it might just show your Nickname. I got my
    first spam unreadable different language spam today :-(.

    Thanks for the help Paul and anybody else with info please feel free to
    chime in.

    Best Regards,

    Liquid, Jul 6, 2006
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