Asus A7A266 DDR-SDRAM upgrade problem

Hi all,

My home-grown computer doesn't seem to want to accept my happy new DDR-SDRAM DIMM. I currently have 1x 256MB of Micron DDR-SDRAM installed, and recently purchased another DIMM of exactly the same type. No problemo, I thought - just bang it in and all shall be fine - 'twas not so. The computer will successfully run through POST but after that, the hard drive will not engage at all and the OS will not boot up. Remove the new DIMM => boots up fine. Put back new DIMM => no bootup. Keep new DIMM (in second slot) & pull out old DIMM => once again boots up fine.


I can see during POST that "512 MB RAM" is correctly identified, so I know I have properly installed the DIMMs. As a further test I installed both DIMMs and tried to boot from floppy => pulls the OS from the floppy fine, but when it comes time to access the hard drive to create that temporary RAM drive (or whatever it is trying to do) it just sits there. Bottom line is: new DIMM installation seems to cause some sort of conflict, and prevents my hard drive from accessing.

Sounds like a motherboard problem to me, but I have no idea how to fix it. Asus's website doesn't offer any help for this problem. Any suggestions would be most appreciated!!

For the record:

Asus A7A266 mobo
256 MB Micron DDR-SDRAM (want to upgrade to 512 MB)
Quantum fireball 20 GB HDD
Hercules 3D Prophet 4500 video card
Creative Ensoniq audioPCI card
300W power supply the usual bits & pieces (DVD drive, LAN card, etc.)
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More about asus a7a266 sdram upgrade problem
  1. Good question, I'm stumped!

    What's the frequency, Kenneth?
  2. found this one on usenet - worth a shot:


    If you have any problems associated with A7A266 or A7M266 boards and have 2
    DIMMs (DDR SDRAM) installed, remove the VIO1 Jumper from the motherboard.
    This will allow the board to function correctly. There have been many posts
    about this issue. By removing the VIO1 jumper, it sets the default Dimm
    voltage to 2.5 volts. Which is the standard voltage needed for dimms.

    There is ALOT of posts ALL over the place about errors installing OS to
    inability to even get past POST and it is due to this problem. This
    information is also confirmed with an ASUS representative.

    <i>It's always the one thing you never suspected.</i>
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