After countless hours of tuning a multi-family (Tahiti and Cypress) GPU rig for scrypt I give up.  It's too unstable.  It uses even more power, causing the heat to go through the roof and the fans get pegged at my limit of 88%.  The hashrate is 15% less on my rig due to the multi-family GPU issues.  Even though a lot of the scrypt coins I was mining were 200% more profitable, it just wasn't worth the work and crashing.