Anyone know what proper setting for 7xxx series card using reaper for litecoin ?

My 7xxx card get half speed of 6xxx series cards. Using 12.2pre.

When I put aggression higher than 12, I get many GPU error on 7xxx card at half hash rate 6xxx, but on 6xxx card, I can set aggression near 22 before 6xxx give me gpu error.

I get near 450KhashS on 6970 but only near 225KhashS on 7950 before GPU error.