I've tried Catalyst 12.8, 12.10, 12.11 beta from 6 to 11, and 13.1 WHQL, and in all of them the GPU core at idle lowers to 300 mhz but the memory clock get fixed at 1200 Mhz (should be 150 Mhz), so the VDDC doesn't lower from 0,90v and the temps at idle fluctuates between 40-42º c (where should be in order of 30º-35º c). The release notes of Catalyst 12.11 beta 6 (and 13.1) says that this issue was especially resolved, but not for me.
Any help would be very appreciated.