Are all GPUs unlocked for overclocking? I know that in CPUs the "K" after the numbers indicates that it can be overclocked. Is there an indication that a GPU is locked or unlocked like the "K"? I'm thinking about getting a R9 270 but I saw a R9 270X for $35 more. I wanted to OC the 270 to save the bucks but I can't tell if the GPU is locked or not. I might not and just spend $35 because I don't want to increase heat output, energy consumption, etc but I'd like to know anyways. Also what is a good program to for OC'ing an AMD card? Thanks.