I have 2x7970,
with 32GB memory i still cant get over intensity 13.. going to intensity 14 chops my hashrate from 580 to 420...
this also aspire to my other rig with 1x7970 and 4x7850
Wonder how people are able to get beyond I13 on amd7xxx series...
All other rigs i have is tweaked intensity on (4x5870,3x6870,2x6970) works like a charm with intensity 16
That much memory is definitely overkill unless you want to do something else with that computer like run a database... Going beyond what is functionally the minimum required to run the OS + mining operation is not going to add any benefit to your operation.
580kh/s sounds about right for a 7970 at I13, though.
You will get HW errors when using cgminer intensity over 13 on the 79xx unless you set the thread-concurrency high enough to prevent worker threads from overwriting each other's memory space when operating at higher intensities. This might not improve your kh/s at all, but you can try setting your thread concurrency for the 7970 to 20480. If you get a cgminer error when starting it with that setting, it means you need to set the GPU_MAX_ALLOC_PERCENT environment variable to 100. You can do that by executing this command (only one time is necessary - don't add to batch file that starts miner)
setx GPU_MAX_ALLOC_PERCENT 100
(case-sensitive, so make sure it's all caps)
use GPU_MAX_ALLOC_PERCENT 100 already. however i dont think ive set threads more then 8xxx something.
If i set shaders to 2048 i get around 20480 threads. will try a bit more.
Found out that if i put the cards at intensity 18-20 i got around 650-700 hash but generate alot of hw error.
Reason for 32gb memory is due to its also my workbench (unity/blender etc).