Sorry if this has been discussed already, I tried searching the forums and found some useful information, but not enough:
I just bought two Gigabyte 6950 1GB and unlocked the shaders; now I am trying to get them to run at 900MHz core or more, while downclocking the memory..
My problem is that whenever I try to bring the memory a single MHz below 775, it jumps to 1250, which is about 15 watts per GPU.
I have found topics related to this where people said they used ATI Tray Tools to downlcock the memory to 300MHz in Windows and verified using GPUZ; however when I tried installing ATI Tray Tools (using all default options), I go to 'Overclock', and the downclock limit for memory is 1000MHz, or if I go to 'Overdrive5' and try to bring memory below 775MHz, it jumps up to 1250MHz.
Are there some custom settings that will allow me to do this in ATI Tray Tools? I saw an option to switch from hardware to software overclocking mode for 'some unsupported boards', and anther option to enable or disable shared memory. I don't really know what I'm doing here, I've never used ATT before, any help would be appreciated!
Note: I have tried Sapphire TriXX and MSI afterburner unofficial overclocking, all with same results, memory jumps to 1250 if I go below 775MHz memory, or over 900MHz core. I am using Catalyst 12.1 WHQL with 2.5 SDK running Windows 7 64bit.
SOLVED! - Sort of. I found a setting to remove the limit for overclock/underclocks under Tools & Options > General Settings > Advanced > Overclock limit
I am now able to downlcock memory to 300 while upping the core to 920 (and higher hopefully!), however that is only GPU 0, I have two 6950's in my system and two 6570 (soon to be replaced), how can I select the other GPUs in my system from ATI Tray Tools?
Note: something odd, when I go to Overdrive5 only GPU 0 is listed...
EDIT: on the bright side, GPU 0 is now happily running at 930 core/225 memory.. Something noteworthy: MH/s starts to drop pretty quick once memory is taken below 225MHz