Hi,
The clock speed depends on GPU load and temperature and there is no guarantee that the clock speed will be changed as per specified in aticonfig command. Here is what man page says
--odsc, --od-setclocks={NewCoreClock|0,NewMemoryClock|0}
Sets the core and memory clock to the values specified in MHz
The new clock values must be within the theoretical ranges provided
by --od-getclocks. If a 0 is passed as either the NewCoreClock or
NewMemoryClock it will retain the previous value and not be changed.
There is no guarantee that the attempted clock values will succeed
even if they lay inside the theoretical range. These newly set
clock values will revert to the default values if they are not
committed using the "--od-commitclocks" command before X is
restarted.
Thanks,