Topic: Underclocking 6990 memory on Linux (Read 1450 times)

Have u tried with 11.7 catalyst. It was released on 27th July 2011.

Unfortunately it doesn't do any magic for me at 11.6 catalyst. Memory clocks can be set only 125 MHz lower than engine, as in aticonfig.

$ atitweak -m 330
Setting performance level 0 on adapter 0: memory clock 330MHz
Setting performance level 1 on adapter 0: memory clock 330MHz
Setting performance level 2 on adapter 0: memory clock 330MHz
Setting performance level 0 on adapter 1: memory clock 330MHz
Setting performance level 1 on adapter 1: memory clock 330MHz
Setting performance level 2 on adapter 1: memory clock 330MHz
Setting performance level 0 on adapter 2: memory clock 330MHz
Setting performance level 1 on adapter 2: memory clock 330MHz
Setting performance level 2 on adapter 2: memory clock 330MHz
Setting performance level 0 on adapter 3: memory clock 330MHz
Setting performance level 1 on adapter 3: memory clock 330MHz
Setting performance level 2 on adapter 3: memory clock 330MHz

$ atitweak -s
0. AMD Radeon HD 6990 (:0.0)
    engine clock 940MHz, memory clock 1250MHz, core voltage 1.175VDC, performance level 2, utilization 0%
    fan speed 100% (960 RPM) (user-defined)
    temperature 73.5 C
1. AMD Radeon HD 6990 (:0.1)
    engine clock 940MHz, memory clock 1250MHz, core voltage 1.175VDC, performance level 2, utilization 0%
    unable to get fan speed
    temperature 68 C
2. AMD Radeon HD 6990 (:0.2)
    engine clock 940MHz, memory clock 1250MHz, core voltage 1.175VDC, performance level 2, utilization 0%
    fan speed 100% (960 RPM) (user-defined)
    temperature 71 C
3. AMD Radeon HD 6990 (:0.3)
    engine clock 940MHz, memory clock 1250MHz, core voltage 1.175VDC, performance level 2, utilization 0%
    unable to get fan speed
    temperature 78 C

For anyone who has been looking for a solid, easy-to-use command line tool that properly underclocks a 6990's memory under Linux, please take a look at this thread:

http://forum.bitcoin.org/index.php?topic=25750.msg320458

This atitweak tool is great and is the only one I've found that will allow me to lower my memory clock from a command line on a 6990 without a hassle.  It's a very solid replacement for aticonfig and/or AMDOvDrvCtrl for things like over/underclocking, fan control, GPU status, etc.

My 6990s now run a lot cooler since I've been able to underclock the memory.

I can't take any credit at all for anything except stumbling across the right thread.  If the tool helps you, flip the guy some coins.