6990 trouble (linux) lowering memory speed with AMDOverdriveCtrl/BIOS flashing

[ixfinito]

Hi,

I'm having a hard time using AMDOverdriveCtrl to achieve results for lowering memory speed. My setup has 3x6990's and I can basically use only the middle card's 2 GPU's because the other two will have crazy hot temperatures.

AMDOverdriveCtrl modifications don't stick and may show as current peaks, but current clocks remain exactly the same. I load the profile for each according to their -h index number. The ranges are lowered and set via aticonfig command, but it doesn't work. Am I missing something here?

In many topics it is suggested that BIOS flashing could be the answer, but can't really find anybody with successful conclusive experience doing that with 6990. I'd appreciate a hint to a guide if there was any.

Is there a solution in linux for my dilemma or should I move to Windows 7 and stick to x6990 (4GPU) setup and find another system for my third 6990?

Your feedback would be greatly appreciated!

Forsythe

http://i53.tinypic.com/112aom9.jpg

http://i55.tinypic.com/2qipy6g.jpg

My configuration:
CoolerMaster HAF X
CORSAIR AX1200 1200W
Asus Crosshair IV Formula
AMD Sempron 140
3 * Asus HD 6990
Kingston 30GB SSD
2GB Ram
Ubuntu 11.04 64-bit

[1715102176]

1715102176

[1715102176]

1715102176

[basementminer]

You can only lower the memory to 125mhz below the core on 69xx

[ixfinito]

You can only lower the memory to 125mhz below the core on 69xx

thanks, so I can move 1250Mhz to 1125Mhz in the GUI of AMDOverdriveCtrl and then run the -b profile in terminal, then use aticonfig to set to gpu speed, 1125Mhz? How significant is this reduction overall for temperature? Does this limitation also exist in Windows?

May I ask what is the ideal voltage for low mid high profiles in AMDOverdriveCtrl?

Many thanks again for any help!