Bitcoin Forum

my 2x 6990 are running at gpu cock 970 and mem clock 870. i have no problem with heat and the cards are at 60-65 celsius.
i want to overclock to 1000,900 or 1100,1000. but using amdoverdrivectrl the cards gets unstable and stop working when on 1000,900. its not heat problem because i have no problem with heat.
to overclock past 1000Mhz core and 900Mhz memory, should i use windows 7 64?

im running ubuntu 64 and amdoverdrivectrl 64.

any suggestions?




~$ aticonfig --odgt --adapter=all

Adapter 0 - AMD Radeon HD 6990
            Sensor 0: Temperature - 62.00 C

Adapter 1 - AMD Radeon HD 6990
            Sensor 0: Temperature - 63.50 C

Adapter 2 - AMD Radeon HD 6990
            Sensor 0: Temperature - 59.00 C

Adapter 3 - AMD Radeon HD 6990
            Sensor 0: Temperature - 64.00 C

~$ aticonfig --odgc --adapter=all

Adapter 0 - AMD Radeon HD 6990
                            Core (MHz)    Memory (MHz)
           Current Clocks :    970           870
             Current Peak :    970           870
  Configurable Peak Range : [500-1200]     [500-1500]
                 GPU load :    99%

Adapter 1 - AMD Radeon HD 6990
                            Core (MHz)    Memory (MHz)
           Current Clocks :    970           870
             Current Peak :    970           870
  Configurable Peak Range : [500-1200]     [500-1500]
                 GPU load :    99%

Adapter 2 - AMD Radeon HD 6990
                            Core (MHz)    Memory (MHz)
           Current Clocks :    970           870
             Current Peak :    970           870
  Configurable Peak Range : [500-1200]     [500-1500]
                 GPU load :    99%

Adapter 3 - AMD Radeon HD 6990
                            Core (MHz)    Memory (MHz)
           Current Clocks :    970           870
             Current Peak :    970           870
  Configurable Peak Range : [500-1200]     [500-1500]
                 GPU load :    99%

I don't think there is any advantage to overclock the mem. I would leave it the same or lower it anyway. OS shouldn't matter really, whatever is your personal preference is IMHO.  If you do switch to Windows there are reports of some having difficulties getting that 4th card to show up. What mobo are you using?

my motherboard is MSI 890FXA-GD70.
the memory is not a problem, on 6990 you cannot downclock memory more then 100mhz under core speed (example: gpu 900 memory 800, gpu 970 memory 870). i think my problem is low voltage, on ubuntu amdoverdrivectrl the max voltage is 1.175.

What's the fan speed and ambient temperature? Mine is at around 70°C with default fan profile.

fan speed is 100% and temps at midday is 65-70 and midnight 55-60 celsius.

this is my cabinet and setup: http://forum.bitcoin.org/index.php?topic=7216.msg283831#msg283831

Did you try with the latest drivers?

Catalyst 11.6 seems to have the restriction removed (you don't even need amdoverdrivectrl)

Adapter 0 - AMD Radeon HD 6990
                            Core (MHz)    Memory (MHz)
           Current Clocks :    955           1250
             Current Peak :    955           800
  Configurable Peak Range : [500-1200]     [1250-1500]
                 GPU load :    0%

Adapter 1 - AMD Radeon HD 6990
                            Core (MHz)    Memory (MHz)
           Current Clocks :    955           1250
             Current Peak :    955           800
  Configurable Peak Range : [500-1200]     [1250-1500]
                 GPU load :    0%

you need amdoverdrivectrl i think.. look at your current clock and current pleak:)
Current Clocks :    955           1250
  Current Peak :    955           800

You might be right, definitely one of those measurements is in error (since you can't have a current above your peak).   Prior to the patch, if you attempted to set the memory clock below 1250 you would get an error and combining that with the fact that I wasn't able to hit 955 or 960 at 1250.  I'm guessing that this is actually running at 800.  I'll see if I can come up with a better test.

you can only set memory clock 100mhz under gpu core clock as i mentioned here:

Cool setup! The temperature is low, are you sure you want to keep the fan at 100% 24/7? Mechanical parts are the ones that are most likely going to break.