You are thinking of the ethlargment pill. It's generally not needed any more as Phoenix miner/ claymore*/ T-rex and others have memory tweaks/ timing built in via command line. It is -straps for Phoenix and --mt for T-rex. Take a look at the readme files for the miners. I am getting 45 MH @ 165 watts with 120 OC and -1000 (linux, -500 win). I could get higher with more power but that seems like a good balance for watts to MH. Claymore isn't supported anymore by the dev so I wouldn't recommend it.