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  • AMD CPU / Memory Controller Limitation

    Regarding my previous post from Nov 17th about Phenom II memory controller problems...page 89 of this AMD Support Document (written back in Feb 09!) http://support.amd.com/us/Processor_TechDocs/41322.pdf outlines the problem. Seems that those of you that have been able to run stably at speeds of 1333 or higher are the lucky ones as the Phenom II CPU (particularly stepping 2, revision RB-C2) memory controller is known by AMD to have a stability issue with more than 1 DIMM on a channel. So, if all else fails, drop you memory down to 1066Mhz and tighten the timings. I did just that with my (4) 2GB F3-10666CL8D modules. I simply down-clocked to 1066Mhz and tightened my timings from 8-8-8-21-2t to 7-8-8-19-1T. My system is now stable and performance is virtually identical at 1066Mhz compared to what it was at 1333Mhz with the looser timings.
    Last edited by GSKILL TECH; 12-04-2009, 12:35 AM.

  • #2
    AMD does not cover erratas... OK, ITS MY FAULT BECAUSE I DIDN'T READ THE CONDITIONS OF WARRANTY
    (inner thoughts: AMD aoskjdoajdso asojdaosdjasdo AMD aosdosdkoad AMD asjsaodasjodjasodjosda AMD aojasojdoasdj!!!!)

    I have Gkill Ripjaws 1600mhz CL9 and a phenom II 955 C2 (beautiful stepping.... "&"!#%AMD!!/#!!!!).
    Do you know what is the bios config that gives me the highest stability and speed?

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    • #3
      Hey Lotsabs im useing a ASUS m4a785td-v evo Mb and 2 sticks of same ram. I was wondering what your voltage for mem is 1.5 or up to 1.6. A GSKILL teck said set at 1.6. Had a lot of trouble with AMD Phenom IIx3 720 giving lots of BSOD,s. Hopefully the settings you provided will help even with others haveing same problems.And with the cold start issue. Thank for any help

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      • #4
        cpu-nb voltage

        Prior to raising the cpu-nb voltage and speed a bit, I had trouble with intermittent errors as described in the tech document with a 550 be rb-ce2. After increasing the cpu-nb to 1.175 and speed to 2400 mhz, I have been running 4gb of f3-12800cl9-2gbnq at 1600mhz no problem at 9-9-9-24 (Prime95 and linx stable for 10+ hours).

        The cpu-nb voltages and speeds are described in http://www.overclockers.com/forums/s...d.php?t=596023 Very helpful for me even though this specific problem isn't discussed.

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        • #5
          shmercer,

          What were all your settings to get your F#-12800CL9-2GBNQ running @ 1600 (other than the timings and CPU-NB voltage, speed)? I have the same RAM, albeit 4GBNQ, and it's rock solid @ 1333, and runs @ 1600 well, passes memtest, but still BSOD's and can't run Prime95 blend for more than 2 seconds...?

          MOBO - Gigabyte MA-770T-UD3P rev 1.1 BIOS F6A
          CPU - AMD Phenom II x2 550 BE running as a X4 B50

          Thanks

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          • #6
            Mike- I upped the dram voltage to around 1.65v. Otherwise everything was auto. After running fine and passing the prime blend tests for 3-5 hours over a couple of days, the BSOD curse started up again.

            I gave up and RMA'd the 550 c2 (I had several other configurations that stress tested fine over a couple of days and then fell apart). Hopefully the memory controller will be better on the 555 c3.

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            • #7
              I have 2 sets of F3-12800CL9D-4GBNQ with a Phenom 2 x4 955, I get random BSOD/Freezes/Restarts if I set it's at 9-9-9-24 I get lockups, if I set everything to auto it is iffy.. Is this because of the above comment?

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              • #8
                Most likely, 2 sets will need to operate at DDR3-1333 8-8-8-24. Only C3 revisions are capable of 8GB DDR3-1600.

                Thank you
                GSKILL SUPPORT

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                • #9
                  So...just how bad would the hit be to put 1 simm in each channel--ie, no dual channel? I hear a lot of different opinions on just what dual channel gives you, real world, and I'm wondering if you can get a stable 1333 or 1600 without dual channel, is that better than 1066 dual? Or constant instability?

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                  • #10
                    Real world, many would not notice a difference. It is just about operating max performance that your system is made for, but you will not notice a performance drop.

                    Thank you
                    GSKILL TECH

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                    • #11
                      Originally posted by GSKILL TECH View Post
                      Only C3 revisions are capable of 8GB DDR3-1600.

                      Thank you
                      GSKILL SUPPORT
                      Good.

                      And Phenom II X6 revisions?

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                      • #12
                        Yes, now that they are released. =)

                        Thank you
                        GSKILL TECH

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                        • #13
                          Dual Channel

                          For my Phenom II, 955, C2, Dual channel would never work (prime 95 lasting less than 10 minutes), but once I split 'em (2 gig in each channel) it's rock stable on prime 95. This is at 1600, with recommended timings. Believe me, I had tried every combination of timings and voltages, and dual channel was always flaky.

                          Benchmarking before/after shows essentially the same results, with a slighter lower (I think 3%) overall RAM score (mostly in large RAM reads I believe), which in the grand scheme of things, is imperceptible.

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                          • #14
                            I have the 1090t amd six core processor and im running at 9-9-9-24-2t timings. Using 4 x 2 gig sticks of 1600 running at 1600. Using the gigabyte GA-890FXA-UD5.

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                            • #15
                              Really running at 1600 (800mhz)?

                              Originally posted by autotech View Post
                              I have the 1090t amd six core processor and im running at 9-9-9-24-2t timings. Using 4 x 2 gig sticks of 1600 running at 1600. Using the gigabyte GA-890FXA-UD5.
                              I was also running dual channel at 1600 with those exact timings with a 16gb kit, same cpu and mobo...then I noticed in CPUZ under SPD that Max Bandwidth reports 667mhz. Can you confirm the same?

                              I tend to wonder that even though its set at 1600 (~800mhz) in BIOS if the memory controller is limited to 667mhz with all 4 slots occupied.

                              From what I read - in dual channel mode were limited to 1333 (~667mhz) with DDR3, anything more would be an overclock? Wondering if it will recognize the bandwidth when set higher (1600+) with a dual channel setup.
                              Last edited by joeuphoria; 06-18-2010, 09:22 AM.

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