Hi guys,
I have had this problem for a while now on a pair of 6870`s xFired. (The LOD issue mainly. textures are blocky unless standing very near to the object)
After reading this and seeing people were having problems with the vram settings i checked mine
they were both set to 300mb approx.
To fix do the following.
Delete the cfg file
DISABLE crossfire
start the game and set the gfx settings to required
check settings in the new cfg file
set the cfg file to read only (IMPORANT step, it seems to reset the vram settings)
REENABLE crossfire
these are my new settings and LOD is now much better
localVRAM=1059373056;
nonlocalVRAM=2147483647;
hope this helps :)