My CORSAIR XMS2 DDR2 800 has lost the ability to run over 770MHz.

Discussion in 'Memory' started by TalonMan, Apr 24, 2008.

  1. TalonMan

    TalonMan [H]ard|Gawd

    Messages:
    1,351
    Joined:
    Feb 16, 2007
    My CORSAIR XMS2 4GB (2 x 2GB) DDR2 800 (PC2 6400) lost the ability to run over 770MHz stable.

    My RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16820145176

    I was running at 3.8GHz on my Maximus SE cool and stable...

    I de-installed my 8600GT, and installed my GX2.

    On the initial boot afterward, I would get a DET DRAM on my LCD Poster. I have had to back down to 3.4GHz to allow my system to boot. I tried for day's but could not get my 3.8GHz back. Heck, I couldn't even get 3.5GHz back. I flashed from BIOS 907 to 1004 to see if it would help, but still my new 3.4GHz max OC Q6600 speed is the best I am able to do. That is because for me to go faster, it requires my RAM with a 400 NB strap to run over 770MHz.

    The 3.4GHz can run at low voltages very stable, with no problems. No matter how much I crank up the voltage though, 3.5GHz or faster is still not bootable without DET DRAM errors.

    My GX2 SSC is operating at stock speed.

    While testing most settings were in auto. Extra performance options in my current saved 1004 BIOS options were only added back in after I return to my very stable 3.4GHz.

    Remember that my ram has indeed worked over 800MHz, and I ran at a stable 3.8GHz for months with my 8600 GT installed operating at a 848MHz DRAM frequency.

    I have set my BIOS to Default settings.
    I then changed my ram's speed to the 800 (Which it is rated at)
    and setting the timings to 5-5-5-18 (which is what my ram is rated at)
    and set my PCI-E Frequency to 110
    and set CPU Ratio Setting to 9
    and setting my strap to 400 and selecting T2, the system boots.

    I begin to walk my system up in speed.
    It's rock solid and passes OCCT and Prime 95 with no issues until I get right back to my new system limit of 3.4GHz

    A 387 FSB with my 400 strap requires my 800 rated ram to run at 774MHz. It will load into windows, but OCCT will error out in about 10 minutes...

    A 388 FSB with my 400 strap requires my 800 rated ram to run at 776MHz. It will load into windows most times, but OCCT will error out in about 10 seconds...

    I kept the 388 FSB to see if I could get that stable, and it gives me my results quick. (Good or Bad)

    I took my 1.8v rated ram, wich Corsair indicated you can run XMS2 at 1.9v, and gradually took it up to 2.1v's. Still my 388 FSB will error out in seconds.

    Keep in mind that this is with Transaction Booster set to disabled, along with Ai clock twister too.

    I can leave all my rams setting to auto except for 5-5-5-18, and the system acts the same.

    Why exactly my ram with an 8600 GT would run at 3.8GHz or even 3.9GHz, but only 3.4GHz with a GX2 SSC installed is a total mystery to me, but my new line drawn in the sand is very real. Running my ram at 770MHz wich my current favorite BIOS settings demand is rock solid, even with Transaction Booster enabled, and Ai Clock Twister set to strong!! She just want to run at 770MHz, but falls apart bad at 776MHz.

    Note: My ram is only operating in single channel mode, due to me only having (1) 2GB stick right now, but it also was in single channel mode when I could run at 3.8GHz too.

    If I change my CPU Ratio Setting to 8....

    With a FSB Frequency of 385, and a NB strap of 400 gives me 3.079GHz, and requires my RAM to run at 770 MHz. (System is rock solid)

    With a FSB Frequency of 387, and a NB strap of 400 gives me 3.10GHz, and requires my RAM to run at 774 MHz. (System did run OCCT error free for 20 minutes)

    With a FSB Frequency of 388, and a NB strap of 400 gives me 3.12GHz, and requires my RAM to run at 776 MHz. (OCCT errored out with code 4 in 30 seconds)

    This info was valuable to me, and indicates that it is not a FSB limit that is holding me back, but rather my RAM's operating frequency.

    So to state my problem correctly, it would be before the GX2 was installed, my RAM would run at 848MHz or even higher. After the GX2 was installed, I now have a RAM frequency limitation of about 770MHz. This is still true, even when I overvolt my 1.8v ram to 2.1v's.
    Whether I run at a CPU Ratio of 8 or 9, now asking my RAM to run at 776MHz will result in Sysyem Stability issues, Core Dumps, and DET DRAM errors on the LCD Poster.


    Before I installed my GX2, this was true about my system:
    Under BIOS 907, and before I installed my GX2, this data was true about my system:

    Recap of my findings:
    So far With the Maximus and my Q6600 GO:
    My CPU Voltage setting of 1.46250v (BIOS), will allow error free Priming with a FSB Frequency 414 giving me 3.7GHz with my 400 NB Strap.
    My CPU Voltage setting of 1.506v (BIOS), will allow error free Priming with a FSB Frequency 424 giving me 3.81GHz with my 400 NB Strap.
    My CPU Voltage setting of 1.51875v (BIOS), will allow error free Priming with a FSB Frequency 428 giving me 3.85GHz with my 400 NB Strap.
    My CPU Voltage setting of 1.51875v (BIOS) starting taking errors 4 minutes into prime with a FSB Frequency 432 giving me 3.8888GHz with my 400 NB Strap.

    I did successfully prime 3.9GHz with a FSB Frequency 435 for 45 minutes, but stopped the test.
    For my system it requires me to set in the BIOS a CPU core voltage of 1.55000v's, and Everest reads 1.53v.
    You also must bump your CPU PLL to 1.60v's.
    1.55 Core and only 1.56 PLL would not Prime 3.9GHz error free.

    Under BIOS 907, and my 8600 GT, these were my settings:

    My 4hour error free run using my 3.8GHz settings. Room temp was a brisk 55°F:
    [​IMG]

    These are my current best BIOS 907 settings for 3.81GHz:

    Under Extreme Tweaker
    Ai Overclock Tuner : Manual
    OC From CPU Level Up : Auto
    CPU Ratio Setting : 9
    FSB Frequency : 424
    FSB Strap to North Bridge : 400
    PCI-E Frequency: 110
    DRAM Frequency: DDR2-848MHz
    DRAM Command Rate : 2T
    DRAM Timing Control: Manual
    CAS# Latency : 5
    RAS# to CAS# Delay : 5
    RAS# Precharge : 5
    RAS# ActivateTime : 18
    RAS# to RAS# Delay : Auto
    Row Refresh Cycle Time : Auto
    Write Recovery Time : Auto
    Read to Precharge Time : Auto

    Read to Write Delay (S/D) : Auto
    Write to Read Delay (S) : Auto
    Write to Read Delay (D) : Auto
    Read to Read Delay (S) : Auto
    Read to Read Delay (D) : Auto
    Write to Write Delay (S) : Auto
    Write to Write Delay (D) : Auto
    DRAM Static Read Control: Enabled
    Ai Clock Twister : Strong
    Transaction Booster : Auto

    CPU Voltage : 1.51250v (BIOS)
    CPU PLL Voltage : 1.58v (BIOS)
    North Bridge Voltage : 1.55v (BIOS)
    DRAM Voltage : 1.80v (BIOS)
    FSB Termination Voltage : 1.44v (BIOS)
    South Bridge Voltage : 1.075v (BIOS)
    Loadline Calibration : Enabled
    CPU GTL Reference : 0.63x
    North Bridge GTL Reference : 0.67x
    DDR2 Channel A REF Voltage : Auto
    DDR2 Channel B REF Voltage : Auto
    DDR2 Controller REF Voltage : DDR2_REF
    SB 1.5V Voltage : 1.50v (BIOS)

    NB LED Selection : NB Volt
    SB LED Selection : SB Volt
    CPU LED Selection : CPU Volt
    Voltiminder LED : Enabled

    CPU Spread Spectrum : Disabled
    PCIE Spread Spectrum : Disabled

    Under Advanced
    And CPU Configuration:
    CPU Ratio Setting : 9
    C1E Suppport : Disabled
    CPU TM Function : Enabled
    Vanderpool Technology : Disabled
    Execute Disable Bit : Disabled
    Max CPUID Value Limit : Disabled

    Under Advanced
    And USB Configuration :
    USB Functions: Enabled
    USB 2.0 Controller : Enabled
    USB 2.0 Controller Mode: HiSpeed
    BIOS EHCI Hand-off : Enabled
    Port 64/60 Emulation : Disabled
    Legacy USB Support : Enabled



    After I installed the GX2, this is the best I can do under BIOS 907 and 1004, with my new 770MHz RAM frequency limit.

    This is only showing 45 minutes run time, but I did Prime error free 7 hours with the exact above posted settings.
    [​IMG]

    Here is my current 1004 Bios settings for 3.465GHz, (With a GX2 installed!):
    Under Extreme Tweaker
    Ai Overclock Tuner : Manual
    OC From CPU Level Up : Auto
    CPU Ratio Setting : 9
    FSB Frequency : 385
    FSB Strap to North Bridge : 400
    PCI-E Frequency: 110
    DRAM Frequency: DDR2-770MHz
    DRAM Command Rate : 2T
    DRAM Timing Control: Manual
    CAS# Latency : 5
    RAS# to CAS# Delay : 5
    RAS# Precharge : 5
    RAS# ActivateTime : 18
    RAS# to RAS# Delay : 3
    Row Refresh Cycle Time : 35
    Write Recovery Time : 5
    Read to Precharge Time : 3

    Read to Write Delay (S/D) : 8
    Write to Read Delay (S) : 3
    Write to Read Delay (D) : 5
    Read to Read Delay (S) : 4
    Read to Read Delay (D) : 6
    Write to Write Delay (S) : 4
    Write to Write Delay (D) : 6
    DRAM Static Read Control: Enabled
    Ai Clock Twister : Strong
    Transaction Booster : Enabled
    Boost Level: 0

    CPU Voltage : 1.40625v (BIOS)
    CPU PLL Voltage : 1.54v (BIOS)
    North Bridge Voltage : 1.43v (BIOS)
    DRAM Voltage : 1.80v (BIOS)
    FSB Termination Voltage : 1.40v (BIOS)
    South Bridge Voltage : 1.050v (BIOS)
    Loadline Calibration : Enabled
    CPU GTL Reference : 0.63x
    North Bridge GTL Reference : 0.67x
    DDR2 Channel A REF Voltage : DDR2_REF
    DDR2 Channel B REF Voltage : DDR2_REF
    DDR2 Controller REF Voltage : DDR2_REF
    SB 1.5V Voltage : 1.50v (BIOS)

    NB LED Selection : NB Volt
    SB LED Selection : SB Volt
    CPU LED Selection : CPU Volt
    Voltiminder LED : Enabled

    CPU Spread Spectrum : Disabled
    PCIE Spread Spectrum : Disabled

    Under Advanced
    And CPU Configuration:
    CPU Ratio Setting : 9
    C1E Suppport : Disabled
    CPU TM Function : Enabled
    Vanderpool Technology : Disabled
    Execute Disable Bit : Disabled
    Max CPUID Value Limit : Disabled

    Under Advanced
    And USB Configuration :
    USB Functions: Enabled
    USB 2.0 Controller : Enabled
    USB 2.0 Controller Mode: HiSpeed
    BIOS EHCI Hand-off : Enabled
    Port 64/60 Emulation : Disabled
    Legacy USB Support : Enabled


    Any thoughts boy's?
     
  2. thebeephaha

    thebeephaha 2[H]4U

    Messages:
    2,054
    Joined:
    May 27, 2007
    Without taking time to read your intensely long post while at work, just judging by your thread title, I'm gonna take a stab and say maybe the RAM is just going bad? You could RMA it maybe?

    Sorry, I just don't have time to read through it all yet.
     
  3. knob

    knob Limp Gawd

    Messages:
    291
    Joined:
    Feb 16, 2008
    holy information overload, batman! /just kidding

    When I first saw you were running a Maximus SE, I wondered what your DRAM volts were, since Asus boards tend to overvolt the sticks by several hundredths of a volt. However, I saw your 3.8 OC was with vDRAM at 1.80 in BIOS... so, not a problem.

    If you still have your 8600, it might be worth popping it back in and seeing if your original OC is reachable again with your originally stable settings. (But if that works, it somewhat implies that your VGA card reduces your XMS2's ability to run at any clock...)