GA-MA785GM-US2H only detecting 1 dimm.

Hello All,

I hope someone can help..

I have the following machine:

Jeantech arctic 600w PSU
GA-MA785GM-US2H rev1.1 running bios M785GS2H11 latest before 12a.
AMD phenom II x6.


I have four sticks of ddr2 ram, but the machine will only ever boot with one in. It does not matter which one, nor which slot it is in.

DIMM is Crucial pc2-6400 (400Mhz)
CT25664AA800
My question is.
Is this a PSU problem? or a motherboard problem, can someone give me some advice on diagnosing this as it is driving me crazy.

Thank you to all in advance.
11 answers Last reply
More about ma785gm us2h detecting dimm
  1. The 6-core CPU's require BIOS F12A at minimum, YES you must Flash your BIOS.

    Use Q-Flash method you'll need a FAT32 Flash Drive.
    Nice 3-part video:
    1. http://www.youtube.com/watch?v=UCCId1Mcrw4
    2. http://www.youtube.com/watch?v=Qlx5GBkiaM0
    3. http://www.youtube.com/watch?v=EX78S4qyHu0

    CPU Support -> http://www.gigabyte.us/support-downloads/cpu-support-popup.aspx?pid=3266
    BIOS -> http://www.gigabyte.us/products/product-page.aspx?pid=3266#dl

    Good Luck!

    edit: Your rig will be like night & day -- your CPU is being dummied down big-time! This probably will correct the other problem(s).
  2. Hello Jaquith,

    Thank you for the speedy answer, I have already tried BIOS F12A , and then stepped back down to F11 as F12A is still in Alpha?
    Sorry I should have explained that in my first post..

    Thank you,

    jaquith said:
    The 6-core CPU's require BIOS F12A at minimum, YES you must Flash your BIOS.

    Use Q-Flash method you'll need a FAT32 Flash Drive.
    Nice 3-part video:
    1. http://www.youtube.com/watch?v=UCCId1Mcrw4
    2. http://www.youtube.com/watch?v=Qlx5GBkiaM0
    3. http://www.youtube.com/watch?v=EX78S4qyHu0

    CPU Support -> http://www.gigabyte.us/support-downloads/cpu-support-popup.aspx?pid=3266
    BIOS -> http://www.gigabyte.us/products/product-page.aspx?pid=3266#dl

    Good Luck!

    edit: Your rig will be like night & day -- your CPU is being dummied down big-time! This probably will correct the other problem(s).
  3. You have choice A & A; A being 12A. I quit looking for additional problems. 12A is not a Beta, GA clearly stipulates a Beta in the BIOS versions by using the word 'Beta.' Most of the Alpha & Beta BIOS are available from http://www.tweaktown.com/

    Once you re-flash to 12A then return ALL of your RAM.

    Compatible -> http://www.crucial.com/store/listparts.aspx?model=GA-MA785GM-US2H
    MOBO specs {Dual Channel} -> http://www.gigabyte.com/products/product-page.aspx?pid=3632#sp

    What you listed CT25664AA800 <-> http://www.crucial.com/search/searchresults.aspx?keywords=CT25664AA800

    You cannot 'make' a Matched Set using 4 even 'same' sticks, it doesn't work that way. RAM is matched into 'Sets' after being tested off the SAME assembly line, there are subtle differences and as soon as there's perfection in both Materials and Production then at that time 'Sets' will be a thing of the past.

    However, you can probably use 2 sticks and break the Dual Channel; use DDR2_1 & DDR2_3 only.
    CPU: | DDR2_1 | DDR2_2 | DDR2_3 | DDR2_4 |
  4. If your doing ANY OC'ing, shut it ALL off......


    Well the BIOS post is correct, you have a New CPU in an old motherboard, go back to F12A (Note: can never tell if they will continue to update BIOS, you may be Alpha forever...)

    Then Boot up with one stick.... Down load and install CPU-Z. Check that your CPU is now correctly identified on the CPU tab screen...

    Then check Memory Tab

    Check DDR2, Channels Single, Size 2048 MBytes, DRAM Freq 400Mhz, CAS 6.....

    Then check SPD Tab

    You should see a JEDEC for 400Mhz, it will list timings, the VOLTAGE should be 1.8 volts


    IF DRAM Freq, CAS, or Voltage is wrong, go into the BIOS screens and set them manually.

    Turn OFF your system: Install a second DIMM. Check your instruction manual to determine if BOTH DIMMs should be in Yellow or BOTH in Red slots...

    Reboot and check CPU-Z. Should on see DUAL channel, and 4096 RAM......
  5. Hello,

    Thanks for the replies jaquith, jb6684.

    I have now done the following

    Bios back to F12A.
    Booted with one stick
    checked CPU-Z all fine readings are below
    400mhz
    cas lat 6
    ras to cas 6
    ras precharge 6
    tras 18
    trc 24
    1.8v

    checked SPD all reads as expected.

    According to manual http://download.gigabyte.eu/FileList/Manual/mb_manual_ga-ma785g%28p%29m-ud%28s%292h_e.pdf

    Should put both dimms in same slot currently they in two closest to cpu, tried putting them in 1+3 but system doesn't get to post.

    Guess I also need to find an internal speaker (UK) as mobo doesn't have one fitted annoyingly.

    Again thanks for all the help so far :).

    jb6684 said:
    If your doing ANY OC'ing, shut it ALL off......


    Well the BIOS post is correct, you have a New CPU in an old motherboard, go back to F12A (Note: can never tell if they will continue to update BIOS, you may be Alpha forever...)

    Then Boot up with one stick.... Down load and install CPU-Z. Check that your CPU is now correctly identified on the CPU tab screen...

    Then check Memory Tab

    Check DDR2, Channels Single, Size 2048 MBytes, DRAM Freq 400Mhz, CAS 6.....

    Then check SPD Tab

    You should see a JEDEC for 400Mhz, it will list timings, the VOLTAGE should be 1.8 volts


    IF DRAM Freq, CAS, or Voltage is wrong, go into the BIOS screens and set them manually.

    Turn OFF your system: Install a second DIMM. Check your instruction manual to determine if BOTH DIMMs should be in Yellow or BOTH in Red slots...

    Reboot and check CPU-Z. Should on see DUAL channel, and 4096 RAM......
  6. gigabyten said:
    Should put both dimms in same slot currently they in two closest to cpu, tried putting them in 1+3 but system doesn't get to post.

    Yes, I know 1+2 & 3+4, I was trying to have you, as I said 'break' the Dual Channel. Mostly, to 'see' if it's a DIMM or Stick issue. If everything was 'fine' it would boot just fine that way - though not in Dual Channel Mode.

    BIOS: {assuming CPU is not OC}
    Memory Clock -> x4
    DRAM Configuration /Enter
    DDR2 Voltage Control -> +0.1v ~ +0.2v
    NorthBridge Volt Control -> +0.1v ~ +0.2v

    CAS# latency -> 6
    RAS to CAS -> 6
    Row Precharge Time -> 6
    Minimum RAS -> 18

    Failure:
    DCTs Mode -> Ganged

    edit: I ALSO said these 'sticks' are NOT listed as compatible for your MOBO. So the rest is round peg into square hole trial and error.
  7. How about one dimm at a time in any slot?
  8. Once again thank you for the feedback,

    It is just a bit strange that the machine can detect the ram at all if it is not compatible?

    Before plumpling for more ram, it would be nice to know that it is just the ram and not something to do with the mobo/psu.

    I guess the easiest thing to do is try and borrow some compatible ram from someone else.

    Thanks for all the help.

    If I do buy some ram which would you recommend? i'm not after o'cing or playing games on this system, it is going to be used for development and vms.

    Best Regards,


    jaquith said:
    Yes, I know 1+2 & 3+4, I was trying to have you, as I said 'break' the Dual Channel. Mostly, to 'see' if it's a DIMM or Stick issue. If everything was 'fine' it would boot just fine that way - though not in Dual Channel Mode.

    BIOS: {assuming CPU is not OC}
    Memory Clock -> x4
    DRAM Configuration /Enter
    DDR2 Voltage Control -> +0.1v ~ +0.2v
    NorthBridge Volt Control -> +0.1v ~ +0.2v

    CAS# latency -> 6
    RAS to CAS -> 6
    Row Precharge Time -> 6
    Minimum RAS -> 18

    Failure:
    DCTs Mode -> Ganged

    edit: I ALSO said these 'sticks' are NOT listed as compatible for your MOBO. So the rest is round peg into square hole trial and error.
  9. I think there may be a bit of confusion here,

    my motherboard is the Giga-Byte GA-MA785GM-US2H (http://www.gigabyte.com/products/product-page.aspx?pid=3447#sp)

    not the GA-880GMA-UD2H

    On the crucial site my motherboard is here:

    http://www.crucial.com/uk/store/listparts.aspx?model=GA-MA785GM-US2H&AID=10402009&PID=3899435&SID=skim1402X558040Xc60ca929c37366eb9aa903950087a6bc&click=true

    and the ram is listed :

    2GB

    Part #: CT25664AA800 • DDR2 PC2-6400 • CL=6 • Unbuffered • NON-ECC • DDR2-800 • 1.8V • 256Meg x 64

    I can swap either stick in and the system boots fine.
    does not post in slot 1+3.

    Once again thanks for all the help so far.
  10. have you tired the unganged mode yet?

    i have the same board, rev 1.1 f12a bios, what is your board revision? i am using 4 x 2gb samsung value ram and it works fine.

    can you borrow ram from a friend? just to try it out
  11. I was, at the time, helping 2 GA MOBO problems - the only oops was the link to your MOBO above. http://www.gigabyte.com/products/product-page.aspx?pid=3447#bios there are 4 versions ALL with 12A BIOS requirement.

    The fact still remains Match Set vs Single Unmatched.

    Ignoring 'Sets', in testing different DIMM Slots even with one stick at a time is a good idea. I 'get' installation recommendations and once the problem is resolved then yep the manual is the way to do it -- you're testing now.

    Next, try DDR2_3 with one stick.

    Problems: RAM vs MOBO vs CPU vs PSU
    In order for the RAM to work both the MOBO & CPU must be running correctly, the RAM must be compatible, and if the goal is to install them in Dual Channel - use Matched set. The fact you can run the PC with 1 stick puts the PSU as a slim to none problem at least regarding the RAM problem.

    Also, during manufacturing production oils are used to bend metal pins -- it's supposed to be cleaned-off. None the less, clean the DIMM slots - dampen the RAM contacts with 90%+ Isopropyl alcohol, place in all DIMM slots, remove, clean RAM contacts, dampen and repeat - remove and allow to dry 5+ minutes; clean ALL DIMM Slots & RAM Contacts. Make certain that the RAM is firmly and fully seated and the DIMM locks are engaged.

    Boot-up.

    Sets vs Unmatched even where I see them work they work at best at default SPD and still have a very high error rate -- therefore, once everything is said and done run Memtest86+ for at least 4-Passes in your case. Any errors exchange the RAM for CT2KIT25664AA800.

    Good Luck
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